Baseball hitters with long contracts run slower to first base, Statcast data shows

Tracking 325 veteran MLB hitters from 2016 to 2024, researchers found that more years left on a contract meant weaker hitting and slower running, while players in a contract year ran faster to first base. Luck measures showed no link to job security.

Illustration of one baseball player jogging and another sprinting toward first base.
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When Major League Baseball hitters have years of guaranteed money ahead of them, they hit worse and run slower. When a contract is about to run out, they sprint harder. That is the conclusion of a new study that uses ball and player tracking data to measure effort more directly than earlier work could.

The paper is by Richard J. Paulsen and Charles E. Jordan of the University of Michigan Department of Sport Management. It was dated June 18, 2026 and posted on SSRN on July 14, 2026.

Separating effort from talent and luck

Economists have long used pro baseball to test agency theory: a worker with a guaranteed contract has less reason to give full effort when that effort is hard to monitor. Earlier studies found that performance rises in a player’s final contract year and dips early in long deals, but they relied on stats such as batting average, which mix effort with ability and luck.

Statcast changed that. Since 2016 it has recorded how fast players run and how hard they hit the ball. The authors sorted nine measures into three groups. Production: weighted on-base average, batting average and on-base plus slugging. Effort: home-plate-to-first-base time, sprint speed and exit velocity. Luck: launch angle and swings and misses inside and outside the strike zone.

Contract data came from the Cot’s Baseball Contracts website, and everything else from Baseball Savant. The sample was limited to non-pitchers with at least six years of MLB service and at least 100 at-bats, giving 882 player-seasons for 325 players. On average a player had about 2.5 years left on his deal, and about 46% of observations were contract years. Player fixed effects strip out each player’s underlying ability, so the comparison is a player against himself at different points in his contract.

Contract years make players faster

Every production measure fell as years remaining rose (p < 0.01), and every one improved in a contract year (p < 0.05). That matches the recent literature.

The new part is effort. More years left meant slower home-to-first times and lower exit velocity, both statistically significant, though the effect on sprint speed was not. In a final contract year, players got to first base faster (p < 0.01) and posted higher sprint speeds (p < 0.05). Exit velocity did not change significantly in contract years.

The luck measures behaved as a placebo should: job security had no significant effect on them in any specification. The running measures were also very stable from year to year, with correlations of 0.934 for home-to-first time and 0.941 for sprint speed, which suggests they capture something consistent about a player rather than noise.

Why teams care

The paper cites earlier work by Paulsen estimating that a player’s lost output in the first year of a multi-year deal costs his team more than $12 million on average, adjusted to 2023 dollars. It opens with Juan Soto, criticised in May 2025 for not running out two balls on back-to-back nights during the first season of a 15-year contract.

The authors acknowledge that sorting measures into effort and luck involved judgement, and that pitchers were left out. Their practical proposal is specific: rather than bonuses for home runs, which could tempt selfish play, teams could tie pay to tracked effort such as running speed from home plate to first base on ground balls.

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