MLB study: Velocity, max efforts likely causing pitching injuries; rule changes should be considered

NEW YORK — A yearlong study by Major League Baseball concluded rising velocities, pitch shaping and emphasis on maximum effort are the likely causes of the vast increase in pitcher injuries and recommended exploring rules changes to address the problem.

The 62-page report released Tuesday said the trends extended to high school and youth baseball because of the incentive to get noticed by professional scouts. The study said there is no evidence linking the pitch clock to injuries.

Illustrated with 26 tables of data, the report was based on interviews with more than 200 people that included former players, front office executives, orthopedic surgeons, athletic trainers, physical therapists, biochemists, major league, college and independent coaches, and international trainers.

“This is a landmark event,” said Glenn Fleisig, director of biomechanics research at the American Sports Medicine Institute in Birmingham, Alabama, who participated in the study. "This is a very important first step, which is to identify the problem and identify the likely risk factors. I am pleased that there was such a consensus. ... The next step is to do various types of research studies."

Possible areas to be studied include offseason training and early season workload, non-game activity, defining and measuring fatigue, biomechanics and pitching style, obtaining more data from international leagues and differentiating results from domestic and international signings.

Major league pitcher IL placements increased from 212 in 2005 to 485 this year and days on the IL rose from 13,666 to 32,257.

“The most significant causes are likely the increased velocity of pitches, the emphasis on optimizing ‘stuff’ (a term referencing the composite movement characteristics of pitches, including horizontal and vertical break and spin rate), and the modern pitcher’s focus on exerting maximum effort while pitching in both game and non-game situations,” the report said.

“Some experts speculated on the potential influence of other factors on the short-term increase in injuries over the past several years, including the lasting effect of COVID-impacted seasons, the introduction of the pitch clock and perceived inconsistencies in the surface grip of the baseball. There was not sufficient consensus or evidence to establish a link between these other factors and pitcher injuries.”

The report said experts recommend MLB consider rules changes to “increase the value of pitcher health and durability and decrease the value of short-duration, max-effort pitching.”

“For instance, playing rules could be adjusted or designed to encourage or require starting pitchers to preserve enough energy to allow them to pitch deeper into games,” the report said. “These incentives could be supported by roster rules that more appropriately regulate the availability of pitchers on a roster or in a team’s bullpen for a given game, including potential changes to the number and frequency of transactions that allow clubs to replace pitchers on their rosters.”

MLB experimented in the Atlantic League with a double-hook designated hitter from 2021-13, in which a team lost its DH if its starting pitcher didn’t finish at least five innings in the last two seasons. MLB lowered the maximum on pitchers from 14 to 13 on June 20, 2022, though it is 14 from Sept. 1 on after rosters expand from 26 to 28. The minimum pitcher IL was restored to 15 days in 2022 after dropping to 10 for the previous five years.

Factors in injuries may include use of weighted balls in training, increased intensity of bullpen sessions, a possible decline in cardiovascular and endurance training, and workload management that incentivizes harder effort over shorter spans.

“Multiple medical experts described new injury patterns that they believe are tied to the focus on velocity and max-effort pitching,” the report said, listing latissimus and teres major tears, rib fractures and oblique strains.

Among the data points: