Studies on Early Specialization in Baseball

In keeping with the previous post about John Smoltz (see below), this study was recently published showing that high draft pick major league baseball players who played more than one sport in high school had reduced rates of injuries.



Single-sport athletes who specialize in baseball at a young age may have a greater predisposition to overuse injury, burnout, and decreased career longevity when compared with multiple-sport athletes. The effect of sport specialization has not been studied in professional baseball players.


Major League Baseball (MLB) players who played multiple sports in high school would experience fewer injuries, spend less time on the disabled list, play more games, and have a longer career than athletes who played only baseball in high school.


Descriptive epidemiology study.


First- and second-round MLB draft picks from 2008 to 2016 who played in at least 1 professional game were included in this study. Athletes who participated in 1 or more sports in addition to baseball during high school were considered multisport athletes, and athletes who participated in only baseball were considered single-sport athletes. For each athlete, participation in high school sports, injuries sustained in MLB and Minor League Baseball, number of days on the disabled list for each injury, number of games played in both leagues, and whether the athlete was still active were collected from publicly available records.


A total of 746 athletes were included in this study: 240 (32%) multisport and 506 (68%) single sport. Multisport athletes played in significantly more mean total games (362.8 vs 300.8; P < .01) as well as more mean MLB games (95.9 vs 71.6; P = .04) than single-sport athletes. There was no difference in the mean number of seasons played in the major leagues (1.8 vs 1.6; P = .15) or minor league (5.25 vs 5.20; P = .23) between multisport and single-sport athletes. Single-sport athletes had a significantly higher prevalence of upper extremity injuries compared with multisport athletes (136 [63%] vs 55 [50%]; P = .009). Single-sport pitchers also had a higher prevalence of shoulder and elbow injuries (86 vs 27; P = .008) and were more likely to have recurrent elbow injuries (33% vs 17% recurrence; P = .002) compared with multisport pitchers.


Professional baseball players who participated in multiple sports in high school played in more major league games and experienced lower rates of upper and lower extremity injuries than players who played only baseball in high school.

Link to the full paper

Hall of Fame Pitcher John Smoltz

I grew up an Atlanta Braves fan and suffered through countless bad seasons. There was an old joke that the Braves were so bad that a guy once left two Braves tickets under the wiper on his car expecting someone to take them. A few hours later he comes out and sees two more Braves tickets with the ones he left.

John Smoltz helped to turn the franchise around and become one of the great pitchers as both a starting pitcher, then relief pitcher and then back to the starting rotation. He had to undergo Tommy John surgery in 2000. As have many pitchers he came back, but I would argue no one had such a successful comeback. In fact, he is the only pitcher in the Hall of Fame to have had Tommy John surgery.

The following clips including Smoltzie talking about this topic.

Players, parents and coaches discuss playing year round

Smoltz’s Hall of Fame Induction speech clip (sorry for the poor sound quality)

Dan Patrick interviews Smoltz (go to 12:54 in the clip, although the rest of the interview is pretty fun)


I decided to start this blog to serve as a space for sharing information on sport sampling, multisport participation and benefits, and the detrimental effects of early specialization. While most of the folks I know get these ideas, I sometimes feel like we are screaming into a tornado.

One catalyst came from a story I have heard where the local youth baseball coach who peaked in high school or maybe junior college ball and who runs a facility and a travel team convinces parents that their son needs to play and practice baseball year-round to have any chance at a college scholarship or to get drafted. The parents may be afraid that their kid will miss out or get behind if they let (much less encourage) their son play other sports.

While I can show papers and studies showing how early specialization is not healthy, they will listen to the coach whose revenue stream depends on kids playing and training at his facility year-round. So while I will share those papers here, I will also share testimonials from athletes and coaches. While appeal to authority is a weak debate tactic, I think we need to bring in “names” to support our case.

So, if you have a video clip or link about multisport, sport sampling and/or early specialization, please feel free to share with me!.