Data Suggests MLB Rule Changes Having Big Impact on Stolen Bases

From sports media talking heads to Walter White himself, you’ve heard the same message a thousand times this offseason: Baseball is going to look different this year.

MLB instituted several significant rules changes, with a broad aim at making games shorter and more action-packed. The former appears to have worked swimmingly during spring training, thanks largely to the pitch clock that has drastically cut down time between pitches. As for the “more action-packed” part, the shift ban has certainly impacted hitters’ success rate on balls in play—but the biggest change might be happening on the base paths.

According to data from the league office, stolen base attempts per game jumped from 1.6 in last year’s spring training to 2.3 this year. Bag swipers were successful more often this year, too: runners had a 77.1% success rate in 2023, up from 71.3% in ’22.

Compare 2023 spring training to ’21 (spring training was abbreviated in ’22), and the numbers are pretty staggering.

There are a few factors that could be the cause of such an extreme uptick. First off is the new bases—they’re bigger this year, up to 18 square inches from 15 in previous years. A bigger target to slide into would clearly give base runners a leg up when trying to catch opposing teams napping.

The pitch clock itself could also play a role in the equation, as it stands to reason that a pitcher who’s feeling a bit more rushed than usual is less effective at holding a runner to a smaller lead. Also a factor is the new limit on pick-off throws, with pitchers only able to do so twice per plate appearance.

Baseball took a big swing at altering the in-game experience in 2023, and it appears the impact of those decisions will be swift.