MLB’s New Baserunning Rules Are Working

The very nature of a major league baseball game has changed dramatically in 2023, perhaps more dramatically than in any season since 1889, when for the first time four balls constituted a walk. The changes are myriad – the pitch clock has markedly sped up the pace of play, for better (mostly) or worse (sometimes). Shifts have been outlawed, at least to the point that three infielders are no longer able to be stationed on the same half of the diamond. And then there are the rules designed to bring back the stolen base.

First, and perhaps most basically, the size of the bases has been increased. A small stroke, but it does enables baserunners to get from Point A to Point B fractionally more quickly, and in a game measured in fractions of seconds, that matters. In addition, pitchers may now make no more than two pickoff throws in any given plate appearance – if a third is attempted and is unsuccessful, a balk is charged.

All of these rules have been test driven in the minor leagues, and this spring the major leaguers took them out for a spin. The spring training results were predictable but understandable in the big picture. The games were an absolute mess as both hitters and pitchers adjusted to the pitch clock, with innings and even games being concluded on automatic balls and strikes. But that’s OK – as my mother told me, there’s a time and place for everything, and it’s called spring training.

Stolen bases were up about 30% this spring, and wouldn’t you know it, they’re up at almost exactly that rate so far in the nascent regular season. All signs point to the speed-based rule changes having the desired effect.

And while all 30 teams got the same amount of notices regarding those changes, and five days is way too early to be drawing any sweeping conclusions, it does appear that some teams planned better for a faster brand of baseball.

10 teams stole more bases in 2022 than the Baltimore Orioles, who had 95. Jorge Mateo (35) and Cedric Mullins (34) had almost three quarters of them. They marched into Boston this past weekend and stole 10 bases in 10 tries, with Mateo and Mullins swiping four apiece. Sure, they pitched awfully and lost two out of three games, but they certainly got some people’s attention.

The Red Sox were in the bottom half of MLB clubs in preventing the steal in 2022, allowing 102 steals in 130 attempts (78.5%), but by no means was this a killing weakness. 2023 starting catcher Reese McGuire actually threw out 7 of 20 (35%) would-be basestealers last season. He was victimized by the O’s 10 for 10 effort this weekend.

The New York Yankees quietly stole themselves some bases (102 for 135, 75,6%) along with all of the home runs they hit in 2022. No one stole more than SS Isiah Kiner-Falefa’s 22, but his replacement, 21-year-old rookie Anthony Volpe, might have that many by the end of June. He stole bases in each of his first three games, leading the club’s overall 6 for 7 stolen base effort.

Through Monday’s games – only five days into the season, with an average of almost exactly four games played per team – only four teams were without a stolen base. Those four are the Tigers, Marlins, Twins and Nationals – all but Minnesota have been regular cellar dwellers in the recent past. It would seem that exploitation of the new speed-friendly rules would be advisable for teams looking for an edge.

Not only is the frequency of the stolen base up sharply in the season’s early days – so is the overall success rate, from 75.4% in 2022 to 84.0% through Monday night’s games. That’s a big deal.

In coming weeks I’ll be taking an ongoing look at the effects of the one rule change that I do not support – the shift elimination. I’ll be letting the sample sizes increase a bit before I take a bit of a deep dive.

As for this one, I’ve seen enough, and I approve. The stolen base, one of the more exciting aspects of the game, had been killed off by an analytical approach that correctly concluded that the cost of a caught stealing was more than the benefit of a stolen base given prevailing success rates that were extremely close to the strategy’s breakeven point. With the chances of being caught down sharply, the stolen base is again “worth it”, and that makes it a good day for baseball.