How to Throw a Screwball: Grip, Mechanics, and Drills for Every Level
Last updated: March 06, 2026
The first time I tried to throw a real screwball, I almost dropped to one knee. My elbow felt like it was being torqued through a pasta machine, the ball squirted off my middle finger, and the catcher actually laughed because the pitch landed roughly where a left-handed batter’s helmet would have been. That was eighteen years ago. I have spent every spring since then refining the pitch, blowing up theories, and putting hundreds of pitchers through the same teaching progression. The screwball is the rarest pitch in modern baseball, and it is also the most misunderstood. This guide is the one I wish someone had handed me in 2008.
I am writing this for the high school sophomore who just watched a YouTube clip of Carl Hubbell, the college pitcher who needs a third pitch that breaks the opposite way of a slider, and the dad coaching a 12U team who keeps hearing his son ask why nobody throws screwballs anymore. By the time you finish reading, you will know the grip, the arm action, the load progression, the catch points to feel, the drills that build it safely, the mistakes that wreck elbows, and the situations where this pitch still wins games in 2026.
What a Screwball Actually Is (and What It Is Not)
A screwball is a pitch that breaks in the opposite direction of a curveball relative to the throwing arm. For a right-handed pitcher, a curveball moves down and to the glove side (toward a left-handed batter). A screwball moves down and to the arm side (toward a right-handed batter, away from a lefty). It accomplishes this through pronation of the forearm at release, which spins the ball with reverse rotation compared to a typical breaking ball.
The screwball is not a circle changeup. The two pitches share a release motion (both pronate), but they are categorized differently. A circle change is a velocity-deception pitch that runs and fades, typically thrown 8-12 mph slower than a fastball with grip-induced friction reducing speed. A true screwball is a breaking ball with a sharper, later vertical drop and tighter spin axis. Hubbell’s screwball was clocked around 60-65 mph compared to his fastball at 86. Mike Marshall, the Cy Young reliever from 1974, threw his closer to 75-78 mph. Daniel Ray Herrera and Brent Honeywell Jr. have thrown the closest to a true screwball in the last 20 years of MLB, and per Statcast tagging the rare instances were classified as “screwball” only a few hundred times across all pitchers since 2008.
Why so rare? Two reasons. First, the pronation motion at extreme finish places stress on the medial elbow and biceps tendon if mechanics are off. Second, modern pitching analytics favor the slider, which is easier to teach, harder to hit, and lower-stress when thrown correctly. But “rare” is not the same as “dangerous when taught right,” and the unpredictability of arm-side break against opposite-handed hitters still has real value. I have seen a college lefty go from getting tagged by righties to dominating them in one offseason just by adding a workable screwball.
Equipment Needed Before You Start
| Equipment | Purpose | Recommended Spec |
|---|---|---|
| Regulation baseballs (12+) | Bullpen reps without rotating wet balls | Leather, raised seams, 5 oz |
| Plyo balls (1, 4, 7, 14, 21 oz) | Pronation isolation drills | Driveline-style or PlyoCare set |
| J-Bands or Jaeger bands | Daily arm care, rotator cuff prep | Light and medium resistance pair |
| Towel | Dry run delivery work | Hand towel, 12-15 inches |
| Throwing partner or net | Repetition and feedback | Pitch-back rebounder for solo work |
| Radar or pocket radar | Velocity comparison vs. fastball | Pocket Radar Smart Coach or similar |
| Slow-motion phone setup | Verifying pronation at release | 120 fps minimum, side and rear angles |
| Athletic tape | Protect middle finger seam pressure point | Pre-wrap and 1-inch cloth tape |
You do not need a pitching mound to begin learning the screwball. The first three weeks are flat-ground work, towel drills, and pronation isolation. Skipping that phase is the most common reason pitchers hurt themselves trying this pitch. If you want to dive deeper into the foundational arm health work that supports any pitch you add, our baseball arm care guide walks through the daily routines I use with every pitcher I work with.
Prerequisites: Are You Ready to Throw a Screwball?
Before you spend a single rep on grip work, run yourself through this honest checklist. Throwing a screwball before your body is prepared is the single most reliable way to develop medial elbow soreness, and I will not pretend otherwise.
- Age: I do not teach the screwball below age 15. The skeletal maturation of the medial epicondyle apophysis is not complete in younger arms, and the pronation forces at release are higher than fastball or changeup loads.
- Pitch arsenal: You should already throw a fastball at command, and ideally a changeup. The screwball is a fourth or fifth pitch, not a starter pitch.
- Arm health history: No active flexor mass soreness, no UCL history, no shoulder labrum issues. If you have any of these, see a sports medicine physician before adding the pitch.
- Mobility: You should be able to pronate the forearm fully without elbow pain. Test this by extending your arm forward, palm up, and rotating the palm to face downward. Smooth full range with no pinching is the green light.
- Mechanical base: Repeatable delivery with consistent release point. The screwball amplifies any mechanical inconsistency you already have.
If you check all five boxes, proceed. If even one is questionable, stay on the changeup until it resolves.
Step 1: The Grip
The screwball grip is closer to a two-seam fastball than to a curveball. There are three main variations, and I teach all three so a pitcher can find what their hand size and finger length supports. The same pronation finish applies regardless of grip, so the choice is comfort and command.
Variation A: Modified Two-Seam. Place your index and middle fingers tight together along the inside seams of a two-seam fastball grip, but shift them slightly toward the arm-side edge of the ball. Thumb sits on the bottom seam directly underneath. This is the grip Hubbell described in his memoir, and it is the easiest to learn first.
Variation B: Off-Center Middle Finger. Index finger curls inward like a knuckle curve, middle finger is the only finger applying spin pressure. Middle finger sits along the inside seam, thumb directly opposite. This grip generates more spin but requires strong middle finger pressure and is harder to command at first. Good for pitchers with longer fingers.
Variation C: The Honeywell Hybrid. Brent Honeywell Jr. talked openly about a grip he learned from his cousin Mike Marshall: index and middle fingers split slightly across the seams (like a splitter, but only mild split), thumb tucked underneath, ring finger touching the side of the ball for stability. This is an advanced grip that produces sharper break but takes longer to develop feel.
Whichever grip you choose, the pressure points matter more than the seam pattern. Pressure should be primarily on the inside half of your middle finger, with the thumb providing a stable base directly under the ball. The index finger is mostly for guidance. If you feel pressure on the outside (pinky side) of either finger, your hand is rotated wrong.
Step 2: The Pronation Release
This is where the screwball is made or destroyed. The pronation at release is the entire point of the pitch. Pronation means rotating the forearm so the palm faces inward and downward (for a righty, the palm finishes facing first base instead of facing the catcher).
Most pitchers already pronate slightly on every pitch they throw. After a fastball release, the forearm and hand naturally rotate inward as part of deceleration. The screwball exaggerates and times this rotation: instead of pronating after release, you pronate through release, applying spin force to the inside-front of the ball.
Here is the cue I give every pitcher: “Turn the doorknob early.” If you imagine your palm is gripping a doorknob, throwing a fastball is letting go of the doorknob right at release. Throwing a screwball is starting to turn the doorknob about a quarter turn before release and continuing to turn it through the ball. The middle finger ends up on the inside of the ball at release, imparting spin from outside-in (relative to your body).
The fingertip exit pattern: middle finger is the last point of contact, exiting on the inside-arm-side of the ball. This is the opposite of a curveball, where the middle finger exits over the top.
Step 3: Arm Slot and Body Position
Most successful screwball pitchers throw from a high three-quarter or true overhand slot. Sidearm pitchers can throw the pitch but usually find the break flattens out into something closer to a sweeping changeup. The high slot maximizes the vertical drop component of the break.
Front-side stability matters more than for almost any other pitch. Because the pronation force pulls your release point arm-side, an unstable glove side will cause you to fall off the mound and lose command. Glove arm should pull tight to the body, elbow tucked into the rib cage, not flying open. Lead leg should hold strong; a soft front knee will cause you to spike screwballs into the dirt arm-side.
The hip-shoulder separation pattern stays similar to your fastball. Do not try to “show” the screwball with body language. The whole value of the pitch is that it looks identical to your fastball out of the hand and only diverges late.
Step 4: Tempo and Velocity Targets
A useful screwball lives 6-12 mph slower than your fastball. If your fastball sits 90, your screwball wants to live 78-84. The slower you throw it, the more break you generate, but the easier it is for hitters to identify and adjust to. The faster you throw it, the smaller the break, but the better the deception.
Most learning pitchers I coach start with a soft screwball (10-12 mph differential) to build feel, then gradually compress that gap as command develops. By month four or five they are throwing it 7-8 mph off their fastball with usable break. Building velocity broadly across all pitch types is its own project; if your fastball is the limiting factor, our guide on how to throw harder covers the mechanical and strength foundations that translate to every pitch you throw, including this one.
Common Mistakes Table
| Mistake | What It Looks Like | Why It Happens | Fix |
|---|---|---|---|
| Wrist snap instead of pronation | Pitch breaks late but loses velocity dramatically | Treating it like a curveball with reversed wrist | Towel pronation drill, slow-motion video review |
| Forced pronation | Sharp medial elbow pain after release | Pronating with elbow rather than full forearm | Stop immediately, return to plyo isolation drills |
| Visible grip change | Hitter picks up the pitch out of the glove | Adjusting grip after the glove tap | Set grip in the glove during sign reception only |
| Glove side flying open | Pitch sails arm-side, no command | Pronation pulling body off line | Glove-tuck cue, towel drill against a wall |
| Throwing too hard early | Flat pitch with minimal break | Pitcher tries to match fastball intensity | Start at 60% effort, build over weeks |
| Index finger pressure dominant | Pitch cuts instead of running | Wrong pressure point on grip | Switch to middle-finger-dominant grip variation |
| Releasing in front of body | Pitch drops too early, hits in front of plate | Trying to “create” the break by altering release | Stay tall, normal release point, trust pronation |
| Thumb migrating up the side | Inconsistent break from pitch to pitch | Thumb climbing during the load | Tape the thumb position for proprioceptive feedback |
| Throwing on tired arm | Loss of command, increased injury risk | Stacking screwballs at end of bullpen | Limit to 8-12 reps per session, early in bullpen |
| Tipping with arm action | Hitter sees a different arm path | Slowing arm to “guide” the pitch | Aggressive arm speed identical to fastball |
The Drills That Build a Screwball
I run pitchers through these drills in order. Do not skip ahead. Each drill builds a specific feel that the next one assumes you have.
Drill 1: Towel Pronation
Take a hand towel folded once. Hold it like the screwball grip. Go through your full delivery and “throw” the towel into a target on the wall about 8 feet away. The towel exaggerates the feel of pronation because of its weight and air resistance. You should hear a snap as the towel turns over. Sets of 10, three sets per session, three sessions per week for the first two weeks before you ever throw a baseball.
Drill 2: Plyo Ball Pronation Isolation
Use a 7 or 14 oz plyo ball. From a kneeling position with your throwing-side knee down, throw the plyo ball into a wall or net 6-8 feet away with a deliberate pronation finish. The heavier ball forces you to feel the rotation and removes the temptation to wrist-snap. The kneeling position eliminates lower-half compensations, isolating arm action. Sets of 8, two sets per session.
Drill 3: Football Spirals
Throw a small youth football short distance (10-15 feet) with the goal of producing a tight spiral that drifts arm-side. The football grip naturally encourages pronation, and the visible spiral gives instant feedback. If your spiral is wobbling or drifting glove-side, your pronation is wrong. Three minutes per warm-up for a month.
Drill 4: Flat-Ground Soft Toss
Standing 30 feet from a partner or net, throw the screwball at 50% effort. Focus only on grip and pronation feel. You should see arm-side run on the ball even at this low effort if mechanics are right. Sets of 10, two sets per session, three sessions per week for two weeks.
Drill 5: Crow Hop Long Toss Screwballs
From 90-120 feet, throw 8-10 screwballs at 70-80% effort with a crow hop. The longer distance lets you see the full break path. This drill should not be done until weeks 4-5 of your screwball program. The principles overlap with our long toss programming guide, which I recommend reading separately if you have not already built a long toss base.
Drill 6: Bullpen Sequencing
In a bullpen, throw a fastball, then a screwball, then a fastball, alternating for 6-10 reps. The point is to feel the contrast in pronation timing. Bullpen reps should always be early in the session when the arm is fresh, never tacked on at the end.
Drill 7: Two-Strike Live At-Bats
Once command is in place (usually month 4-5), face hitters in live at-bat work and throw the screwball only in two-strike counts. This pressure-tests command under game conditions and trains your sequencing instincts.
A Sample 12-Week Build Program
| Week | Focus | Reps Per Session | Frequency |
|---|---|---|---|
| 1-2 | Towel drill, plyo isolation, no baseballs | 30 towel + 16 plyo | 3x/week |
| 3-4 | Flat-ground catch, football spirals, 50% effort screwballs at 30 ft | 20 screwballs | 3x/week |
| 5-6 | Long toss screwballs at 70% effort, 60-90 ft | 15 screwballs | 2x/week |
| 7-8 | Bullpen sequencing, mound work, 80% effort | 10-12 screwballs in 35-pitch bullpen | 2x/week |
| 9-10 | Command refinement, target work, mixing speeds | 15 screwballs in bullpen | 2x/week |
| 11-12 | Live at-bats, two-strike usage, full intensity | 5-8 in live setting | 1-2x/week |
The 12-week program assumes you are already in-season or have a baseline throwing program. Off-season pitchers can compress weeks 1-2 if their arm is conditioned, but never compress the mound progression in weeks 5-8. That is where injuries happen.
How to Use the Screwball in Games
The screwball is not a primary pitch. It is a weapon you deploy 8-15% of the time, primarily against opposite-handed hitters. Here is the situational logic I teach.
Best counts: 0-2, 1-2, and 2-2. The screwball as a put-away pitch is brutal because the late drop generates swing-and-miss or weak ground balls.
Best targets (RHP vs LHB): Down and in to the lefty’s back foot. The pitch starts at the inner half and runs in toward the hitter’s hands while dropping. Lefties roll over it consistently when located there.
Best targets (LHP vs RHB): Same pattern, mirrored. Down and in to the righty’s back foot. This was Hubbell’s bread-and-butter pitch against right-handed hitters in the 1930s and is the same logic Daniel Ray Herrera used as a lefty reliever in the late 2000s.
When to avoid it: Same-side matchups. The pitch breaks toward your own dugout against same-handed hitters and into their barrel. It also loses effectiveness against power hitters who can stay back; mid-contact hitters and free-swingers are the classic targets. The screwball fits naturally into a broader sequencing plan, and if you want to think more deeply about how to weave it into at-bats, our pitch sequencing guide walks through the count-by-count logic in detail.
Advanced Tips From the Bullpen
These are the small adjustments that take a workable screwball to a put-away pitch. None of them are appropriate before you have a six-month base of the foundational program.
- The two-speed screwball. Develop both a “show” version at 12 mph slower than your fastball with bigger break, and a “tight” version at 7 mph slower with sharper late break. The slow version is for early counts, the tight version for two-strike counts.
- Mirror tunnel work. Find a tunnel partner pitch (usually your changeup or two-seam fastball) that shares the first 30 feet of flight path with the screwball. The two pitches should look identical until the last 15 feet. Tunnel work in the bullpen with a string or laser line at 30 feet is the most efficient way to build this.
- Pronation throughout the warm-up. Pitchers who pronate aggressively on every pitch (even fastballs) end up with healthier arms long-term, and they also disguise the screwball better. The screwball does not stand out from your normal release pattern.
- Self-scouting. Record yourself on phone slow-motion every two weeks. The screwball is so feel-based that drift in mechanics is hard to notice without video. I have caught my own pitchers losing a quarter inch of pronation arc on tape that they swore felt identical.
- Never throw it cold. The screwball requires fully warm flexor mass and shoulder. Throwing it on a cold morning at 6 a.m. before a long-toss warm-up is one of the fastest paths to medial elbow soreness.
- Use it sparingly. Pitchers who throw too many screwballs lose feel for the rest of their arsenal. I cap my pitchers at 15 in any single bullpen and 12 in any single game.
Tracking Your Progress
I use four metrics to evaluate a developing screwball. None of them require expensive technology.
- Velocity differential: Measured with a pocket radar. You want a stable 7-12 mph gap with your fastball.
- Strike percentage: Track first 30 screwballs in any bullpen month. You should hit 55% strikes by month three, 65% by month six.
- Visual break: Stand behind a catcher with a phone at 240 fps and measure horizontal break in inches against a tape-measured backdrop. A workable screwball generates 8-14 inches of arm-side run.
- Hitter feedback: In live at-bats, track ground-ball rate against opposite-handed hitters. A screwball above 60% ground-ball rate is doing its job.
Pitch Comparison: Screwball vs Other Arm-Side Pitches
| Pitch | Velocity Off Fastball | Horizontal Break | Vertical Drop | Release Mechanic | Difficulty to Learn |
|---|---|---|---|---|---|
| Screwball | -7 to -12 mph | 8-14 in arm-side | 4-7 in below fastball | Aggressive pronation through release | Very high |
| Circle Changeup | -8 to -12 mph | 10-16 in arm-side | 3-6 in below fastball | Mild pronation, friction grip | Moderate |
| Two-Seam Fastball | -1 to -3 mph | 6-10 in arm-side | 1-3 in below 4-seam | Standard fastball release | Low |
| Sinker | -1 to -4 mph | 8-12 in arm-side | 3-6 in below 4-seam | Slight pronation, two-seam grip variation | Low to moderate |
| Splitter | -6 to -10 mph | 2-4 in arm-side | 6-10 in below fastball | Fingers split, neutral release | Moderate to high |
The screwball’s distinctive contribution is the combination of late vertical drop with sharp horizontal run. A two-seam fastball runs but does not drop. A splitter drops but does not run. A circle change does both gently. The screwball does both aggressively, which is why it remains valuable as a third or fourth pitch despite being hard to throw.
Frequently Asked Questions
Will throwing a screwball hurt my arm?
Not if it is taught and used correctly. The myth that screwballs ruin elbows comes from pitchers who tried to throw them with a curveball-style supination flip rather than a smooth pronation. Multiple sports medicine studies, including a 2002 Andrews Institute biomechanical analysis, found pronated pitches actually generate less medial elbow stress than supinated pitches like the curveball, when mechanics are correct. The risk is in how you teach and use it, not the pitch itself.
How long does it take to learn?
For an established pitcher who already commands a fastball and changeup, 12 weeks gets you a usable bullpen pitch and 6 months gets you a game-ready pitch. Mastery, in the sense of being able to throw it for strikes in any count, takes 18-24 months of consistent work.
Can I throw a screwball at any age?
I do not teach it below age 15. The medial epicondyle apophysis is still developing in younger arms, and any breaking pitch with elevated forearm rotation forces is not appropriate for that population. Stick to fastball and changeup until physical maturity.
Why are there so few MLB screwball pitchers?
Three reasons. First, the slider does most of what the screwball does for the dominant pitching hand and is much easier to teach. Second, modern player development invests heavily in pitches with strong analytic data, and the screwball is so rare that there is limited public Statcast data to model it. Third, organizational coaches are often unfamiliar with how to teach pronation-dominant pitches and play it safe with familiar offerings.
Is a screwball legal?
Completely legal at every level of baseball. There is nothing in MLB, NCAA, NFHS, or Little League rules that restricts grip or pronation patterns. Confusion sometimes comes from old comments about Hubbell or Marshall having an “unfair” advantage, but those were aesthetic complaints, not rule violations.
What is the difference between a screwball and a reverse slider?
Some pitching coaches use the term “reverse slider” interchangeably with screwball. Mechanically they are similar pitches, but the velocity profile differs. A reverse slider tends to be thrown harder (3-5 mph off fastball) with smaller break. The screwball is the slower, bigger-breaking version of the same family.
Can a left-handed pitcher throw a screwball?
Absolutely, and historically lefty screwball specialists have been among the most successful. Hubbell, Warren Spahn, Tug McGraw, Fernando Valenzuela, and Daniel Ray Herrera all used the screwball as lefties to neutralize right-handed hitters. The mechanics mirror exactly: pronation toward third base instead of first base.
Should I throw a screwball if I already have a strong changeup?
Probably not as your fourth pitch unless you have a specific need. If your changeup already gets opposite-handed hitters out, you do not need to add a similar shape. The screwball makes more sense for pitchers whose changeup lacks late drop, or for relievers facing platoon-disadvantaged hitters in late innings.
How is screwball spin axis measured?
Spin axis on a Trackman or Rapsodo unit will read between 1:30 and 3:00 for a right-handed pitcher (mirrored 9:00-10:30 for a lefty). Compare to a 12:00 four-seam fastball or a 6:00 curveball axis. The diagonal axis is what produces the simultaneous arm-side run and downward drop.
What is the typical spin rate?
Workable screwballs spin between 1,800 and 2,400 rpm. Higher spin generates more break. Lower spin around 1,500 rpm tends to flatten out and become a non-competitive pitch. If you have access to a Rapsodo unit, monitor your spin rate as a feedback metric in bullpens; the rate is often a leading indicator of mechanical drift.
Final Thoughts From the Mound
The screwball is the pitch I get the most questions about and the pitch I am most cautious about teaching. It rewards patience and punishes shortcuts. The pitchers I have seen succeed with it all share three traits: they spent at least eight weeks on flat-ground pronation work before throwing one off a mound, they used video review religiously to catch mechanical drift, and they kept the pitch as a small percentage of their arsenal rather than over-relying on it.
If you do this right, by the end of next season you will have a pitch that very few hitters in your league have ever seen. They will tell their teammates that “the lefty’s changeup falls off the table” or that “his sinker breaks like a wiffle ball,” and you will know they are talking about a pitch they cannot identify because they have never faced one. That, more than any single strikeout, is the reward for the work.
Take the program slowly. Respect the prerequisites. Trust the pronation. The screwball will not betray you if you do not betray it.
