In Division I baseball, pitchers from warmer states are undergoing Tommy John surgery (UCL reconstruction) at significantly younger ages than their cold-weather peers. The data is stark: freshmen and sophomores from warm-weather climates suffer UCL injuries at nearly double the rate of cold-weather pitchers. And while cold-climate pitchers eventually catch up in injury totals, the earlier timing in warm-climate athletes could have profound implications for their long-term careers.

A recent study published in the Orthopaedic Journal of Sports Medicine analyzed 320 NCAA Division I pitchers who underwent UCLR between 2015 and 2022. When researchers sorted pitchers by college geography—warm vs. cold states—they found a clear trend: pitchers who grew up and played in warm states were more likely to break early (Pescatore et al., 2025).

What the Study Found

• Freshmen from warm states were 1.94 times more likely to undergo UCLR than freshmen from cold states (P = .0032).
  
  
• Sophomores from warm states were 2.04 times more likely to suffer a UCL injury than cold-state sophomores (P = .0003).
  
  
• Warm-weather pitchers made up 49.4% of UCLRs, despite comprising just 36.3% of the D1 pitching population.
  
  
• Overall UCLR rate was 0.0156 per pitcher in warm states vs. 0.0091 in cold states (P = .00011).
  
  
• Pitchers from warm-weather high schools had a 1.35 times higher rate of UCLRs as underclassmen than those from cold-climate high schools (P = .041).
  
  
• Cold-weather pitchers tended to break later — most UCLRs in this group occurred during their junior year.
  
  
• The geographic UCLR gap never entirely closed: by senior year, warm-weather pitchers still had the highest risk (2.49 times higher than cold-weather seniors; P = .0159).
  
  

Why This Matters

For years, the conversation around arm injuries has focused on how much a pitcher throws, not necessarily when they start accumulating those reps. But this study puts an uncomfortable spotlight on early specialization and year-round play.

Athletes in warm climates simply have more access to the field. More bullpens. More games. More showcases. More “development.” But that added exposure may be front-loading stress at a time when tissue structures are still maturing. And with more recent research suggesting that the older an athlete is when they undergo UCLR, the better their recovery and career trajectory, this becomes more than a geographic curiosity; it becomes a developmental red flag.

From a physiological standpoint, the authors also highlight the role of temperature: warmer weather increases muscle elasticity and range of motion, potentially allowing pitchers to move faster and throw harder earlier, but possibly before their UCL is fully ready to handle those loads (Pescatore et al., 2025).

How We Apply This at VeloU

This isn’t about fear-mongering or telling warm-weather athletes to stop throwing. It’s about load history. At VeloU, we prioritize understanding each athlete’s prior throwing volume, not just their current activity. Two athletes with similar mechanics and strength may respond completely differently to a training stimulus if one has already accumulated 300 more innings since middle school.

It’s also why we don’t rush into max intent training with young throwers, especially those coming from warm-weather states with heavy summer schedules. The earlier the exposure, the earlier we need to build tissue tolerance before maxing out output.

Because if this study is correct and earlier injuries are correlated with worse long-term outcomes, then the goal isn’t just to throw hard, but to stay in the game long enough to make it matter.

This article is part of Applied Baseball Science by Dr. Nicholas Serio, where we break down the biomechanics, performance science, and injury research shaping the modern game. Powered by VeloU (Velo University) — where research meets real-world baseball.

Reference

Pescatore, S. M., DeShazo, S. J., & Weiss, W. M. (2025). Frequency of Tommy John surgery in NCAA Division I college pitchers versus weather conditions. Orthopaedic Journal of Sports Medicine, 13(1), 1–8. https://doi.org/10.1177/23259671241311601