Baseball Injuries: Elbow, Shoulder, Pitch Counts and When to See a Pro

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A Saturday Little League game, fourth inning. The 11-year-old on the mound shakes out his arm between pitches, and his dad in the bleachers notices. In a big-league bullpen, a reliever feels a twinge on the inside of his elbow and walks off with the trainer. The arm takes a beating, and the ball, the bat and the ground do the rest. This page covers the most common baseball injuries: the elbow (UCL and “Little League elbow”), the shoulder, overuse and pitch counts, hamstrings, getting hit by a pitch, commotio cordis and concussion. You’ll find what lowers the risk and when to get help.

This is general information, not medical advice. If you’re hurt, see a sports medicine doctor, a physical therapist (PT) or a certified athletic trainer (AT). For the big picture of the sport, start at our baseball hub.

How baseball players get hurt

The American Academy of Orthopaedic Surgeons (AAOS) says most baseball and softball injuries are mild: strains, sprains, cuts and bruises. The serious ones mostly come from contact with a ball, a bat, the ground, a wall or another player. On top of that, throwing over and over strains the shoulder’s rotator cuff and the elbow’s ulnar collateral ligament (UCL). A national study of US high school baseball counted 1.26 injuries per 1,000 athlete-exposures (one player in one practice or game). The shoulder led (17.6%), then the ankle (13.6%), head and face (12.3%), hand and finger (8.5%) and thigh (8.2%). Most cost less than a week, but 9.4% needed surgery. About one in nine came from a batted ball, usually to the head, face or teeth.

The elbow: UCL tears and Tommy John surgery

The UCL runs along the inside of the elbow and holds the joint together when you throw. AAOS calls it the most commonly injured ligament in throwers. The damage ranges from irritation to a full tear. The usual signs are inner-elbow pain and lost velocity. Replacing the ligament with a tendon graft is called UCL reconstruction, or “Tommy John surgery”, after the pitcher who had the first successful one in 1974.

It’s common at the top. In a survey of 5,088 professional players, 25% of major league pitchers had had UCL reconstruction, against 15% of minor league pitchers and 3% of non-pitchers. Return isn’t guaranteed. AAOS says it may take 6 to 9 months or more to get back to competitive throwing. In a study of MLB pitchers who had a first UCL operation in 2018 to 2023, 71.9% were back pitching within two years and 82% within three. When rest and rehab are enough, AAOS says athletes can often throw again in 6 to 9 weeks.

Young arms: Little League elbow

In a growing elbow, the weak spot is the growth plate on the inner knob, which is weaker than the ligaments and muscles attached to it. Repeated throwing pulls on it, and AAOS calls the result “Little Leaguer’s elbow” (medial epicondyle apophysitis): aching or sharp pain on the inside of the elbow after pitching. Ignore it and keep throwing, and the pull can tear tissue away from the bone and disturb growth. A less common problem, osteochondritis dissecans, causes pain on the outside of the elbow.

AAOS says a child should stop throwing with any of these: elbow pain or swelling, especially with lost velocity; a “pop”; numbness or tingling; less motion; or an elbow that locks. Coaches and parents should take every complaint of arm pain seriously and get medical care for pain that doesn’t go away or returns every time the child pitches again. More on growing players on our youth baseball page.

The shoulder

AAOS says the late-cocking and follow-through phases of a pitch put the greatest force on the shoulder, and the rotator cuff and labrum are the parts most at risk. Common throwing injuries include rotator cuff tendinitis and tears, SLAP tears of the labrum, biceps tendinitis and internal impingement.

Motion matters too. In professional pitchers, losing more than 5 degrees of total rotation in the throwing shoulder was linked to more injuries. A PT or AT can measure it in preseason.

Overuse and pitch counts

This is the part of baseball health with the strongest evidence. In a study of adolescent pitchers who needed shoulder or elbow surgery, the factors most strongly linked to injury were overuse and fatigue. The injured pitchers pitched more months a year, more games and more pitches, threw harder, pitched more showcases and pitched more often with a tired or sore arm. In a 10-year study of 481 youth pitchers, those who pitched more than 100 innings in a year were 3.5 times as likely to be seriously injured. In another study of 476 pitchers aged 9 to 14, half had arm pain in one season, and pain rose with pitches thrown.

That’s why MLB and USA Baseball built Pitch Smart. Its daily maximums are 50 pitches at ages 7–8, 75 at 9–10, 85 at 11–12, 95 at 13–16, 105 at 17–18 and 120 at 19–22, with required rest days that rise with the pitch count (the full table is on our training page). It also says to avoid pitching on three straight days, avoid pitching in more than one game a day, avoid playing catcher while not pitching and avoid playing for more than one team at a time. Little League uses its own pitch-count rules with the same daily limits for most ages. AAOS adds: limit the number of teams a child plays on in one season.

Hamstrings

Hamstring strains are the most common injury in professional baseball. MLB’s injury tracking system counted 2,633 of them in the majors and minors from 2011 to 2016. More than half happened while running the bases, most often home to first, and infielders had the biggest share. The average injury cost 14.5 days. Pitchers aren’t spared: in a 10-season MLB study, the landing leg was hurt in about two of three pitchers’ hamstring injuries. MLB athletic trainers, PTs and strength coaches rated managing workload and regular high-speed running as the most effective prevention: sprint a little all year so the first dash to first isn’t a shock.

Hit by a pitch, and commotio cordis

In five seasons of MLB and minor league data, 2,920 hit-by-pitch injuries cost 24,624 days. The hand and fingers were hurt most (21.8%), then the head and face (17.0%) and elbow (15.7%), and 5% were concussions. Injury rates rose with pitch speed. AAOS recommends a batting helmet at the plate, on deck and on the bases, a face guard on the helmet, and suggests that batters consider elbow and shin guards on the side facing the pitcher. Softer baseballs lower the risk in youth leagues, and players should be taught how to get out of the way.

Commotio cordis is rare but deadly: a blow to the chest at exactly the wrong moment of the heartbeat stops the heart. In the US Commotio Cordis Registry, the people affected were 15 years old on average and 95% male. Survival has improved with faster response, and an automated external defibrillator (AED) on site was protective. AAOS’s advice: know where the nearest AED is at every field. For high school catchers, the NFHS has required a chest protector that meets the NOCSAE commotio cordis standard since January 1, 2020. NOCSAE itself says no chest protector can prevent every cardiac injury, so the AED and fast CPR still matter most.

Concussion: recognize and remove

A fastball to the helmet, a foul tip off the catcher’s mask, two outfielders colliding. MLB adopted a standardized concussion protocol in 2011. The CDC’s HEADS UP program asks coaches and parents to watch for a player who looks dazed, is slow to answer or moves clumsily. Listen for headache, dizziness, nausea, blurry vision, sensitivity to light or noise, or feeling foggy.

• Remove the player right away. When in doubt, sit them out.
• Keep them out for the rest of the day and until a healthcare provider clears them.
• Return in steps, which usually takes a week or more.
• Call 911 for a headache that gets worse, repeated vomiting, seizures, passing out, slurred speech or unequal pupils.

Prevention that works

• Count pitches and rest the arm. Follow Pitch Smart or your league’s rules, and take months off from throwing every year. See our recovery page for the days between outings.
• Arm care exercises. In a Japanese study of players aged 8 to 11, a program of 9 strengthening and 9 stretching exercises, done in the warm-up or at home at least once a week, cut medial elbow injuries about in half (0.8 vs 1.7 per 1,000 athlete-exposures). Many programs use light resistance bands like the THERABAND Beginner Kit. A PT or AT can show the right exercises.
• Warm up and cool down. AAOS suggests easy calisthenics and light running, then gentle stretching. Many players also roll their legs on a foam roller like the TriggerPoint GRID 1.0 after practice.
• Safer fields and gear. AAOS favors breakaway bases (many injuries happen while sliding), a double first base, a pre-season physical and catcher’s gear with a long-model chest protector and throat guard. Players who have rolled an ankle before often wear a lace-up brace such as the McDavid 195; our ankle brace guide compares more.

When to see a doctor, PT or athletic trainer

• Pain on the inside of the elbow, or a pitcher who suddenly loses velocity.
• A “pop” in the elbow or shoulder, a joint that locks, or numbness and tingling in the hand.
• Arm pain that comes back every time a young pitcher throws again.
• A sharp pull in the back of the thigh while running.
• Any concussion signs, or any hit to the chest followed by collapse (start CPR, call 911, get the AED).

AAOS’s return-to-play rule: symptoms completely gone. For a joint, that means no pain, no swelling, full motion and normal strength. After a shoulder or elbow overuse injury, the player returns through a gradual throwing program. After a concussion, a doctor must give clearance.

Baseball injury FAQs

What is the most common injury in baseball?

In US high school baseball the shoulder is the most injured body part, and sprains and strains are the most common types. In professional baseball, hamstring strains are the most common injury, mostly from base running.

What is Little League elbow?

It’s irritation of the growth plate on the inside of a young thrower’s elbow, caused by repeated throwing. It shows up as pain on the inner elbow after pitching. AAOS says to stop throwing and see a doctor if there’s pain, swelling, lost velocity, a pop, numbness, less motion or locking.

How long does it take to come back from Tommy John surgery?

AAOS says it may take 6 to 9 months or more to return to competitive throwing. Many pitchers take longer. In a recent MLB study, about 72% were back within two years of a first UCL surgery and 82% within three. Your surgeon and PT set the timeline.

Do pitch counts really prevent arm injuries?

Research ties arm pain and injury to how much young pitchers throw and to pitching while tired. Pitch Smart’s limits and rest days are built on that research, and counting pitches is the simplest way to follow them.

Can a baseball to the chest stop the heart?

Rarely, yes. It’s called commotio cordis. Fast CPR and an AED save lives, so keep an AED close to every field. High school catchers must wear a NOCSAE-standard chest protector.

Count the pitches, rest the arm, warm up properly, wear the helmet and know where the AED is. Keep going with our training, game-day and recovery guides, our resistance bands guide, and see how another sport handles it on our soccer injuries page.