Among the rule changes implemented by Major League Baseball prior to the current season, the introduction of the pitch clock has drawn the most attention and bandwidth. That's understandable given that the timer has helped shave roughly a half-hour off the average game time and improved the general pace of things. However, that's not the only structural innovation that's changed baseball for 2023 and probably beyond.
Other changes designed to revive the running game in MLB also appear to be making a demonstrable difference in how baseball is played at the highest level, and this change merits further exploration. Since the effects of the pitch clock have been amply chronicled, let's indeed take a look at how MLB has brought back the stolen base and what it might mean for baseball moving forward (all stats current as of Tuesday).
Why it's happening
The biggest factor for elevated stolen base rates (more on that below) is the new limitation on pitcher disengagements and, by extension, pickoff throws. Pitchers now are allowed to step off the rubber just twice during a plate appearance, whether merely to reset or to throw over to an occupied base. Prior to this season, there was no limit on step-offs, so this is indeed a major change. Obviously, base-runners are emboldened by knowing exactly how many times a pitcher can make a move during a given batter-pitcher encounter, and that knowledge affords more aggressive lead-offs and, once two pickoff moves are exhausted, a green light that's greener than ever before.
Playing a secondary role are the enlarged bases. First, second, and third bases are now 18 squares inches in size – up from the 15 square inches that prevailed for more than a century. That swollen bag makes for a larger sliding target, and it also reduces the distance between first and second and second and third by 4 1/2 inches each. While that may not sound like much at first blush, think about how many plays at the bag in the past seem to be determined by a hairsbreadth or so.
As well, the rates of singles plus walks – or runners on first base and often with an opportunity to steal of base — is up somewhat in 2023 relative to 2023. The modestly increased batting average on ground balls probably has something to do with that, and in turn the restrictions on infield over-shifts probably haave something to do with that elevated batting average on ground balls.
How we know it's happening
This one's pretty straightforward. MLB teams right now are averaging 0.68 stolen bases per game. If that holds up, then it will be the highest such figure since 1999, or almost a quarter-century. It's not just a matter of raw steal totals, too. Base-stealers in 2023 have been successful almost 80% of the time (78.8%, to be precise). That's on target to be the highest stolen-base success rate in the history of MLB. Success rates have trended higher and higher over the years, but 2023's rate is notable even by contemporary standards. The current record is the 75.7% success rate of 2021.
All of this is important because in the analytics age teams have properly recognized the value of avoiding outs on offense. This is primarily exhibited by the emphasis on a hitter's on-base percentage (or, if you invert it, rate of out-avoidance), and it also means taking care not to make outs the bases. That latter desire has led to less and less base-stealing over the years. For teams to get more active on the paths, it has to be worth it to them. Succeeding roughly eight out of every 10 attempts, which is what's happening this year, certainly qualifies as "worth it to them." That's vital because teams rationally won't just rack up stolen bases if it also means racking up outs. So far, the 2023 season has given us volume and rate-based success. It takes both for the trend to continue.
What it could mean
As it turns out, a number of notable speed-merchant benchmarks could be in the offing. First, let's circle back to that aforementioned success rate of 79.7%, which is on pace to be an all-time record. Drill down to the next layer, and we still have records:
Base-stealers this season have a 77.2% success rate when going for second base. That would break the record of 75.7 percent set in 2021. When going for third base, base-stealers this season have a success rate of 93.0% (!). That would break – no, pulverize – the current record of 80.9% set in 2012. Specifically, thieves this season are 66 for 71 when attempting a steal of third base.But wait – there's more:
Arizona's Corbin Carroll and Anthony Volpe of the Yankees are on pace to become the first rookies to steal 50 or more bases since Billy Hamilton in 2014. Not since 1992 have multiple rookies logged 50 or more steals, and overall that's happened just twice since 1900. Overall, six players this season are presently on pace to steal at least 50 bags. That hasn't happened since 2007. Another three players this season are just barely off the 50-steal pace. Cedric Mullins and Jorge Mateo of the Orioles are each on pace to top 50 steals this season. Not since the Montreal Expos in 1991 has a team had two players record 50 or more steals.At this writing, league leader Ronald Acuña Jr. of the Braves is on pace for 84 stolen bases. That (projected) total hasn't been topped since the peerless Rickey Henderson stole 93 bases as a member of the Yankees in 1988. Chase Utley of the 2009 Phillies holds the all-time record for most steals in a season without getting caught even once (23). We're admittedly getting ahead of ourselves with this one, but right now in 2023 a whopping 12 players are on pace to top that mark. They're led by Mullins (nine steals without being caught) and those rookies Carroll and Volpe. At the team level, the Cleveland Guardians right now pace the league with 28 steals, and that puts them on pace for 197. If they up that clip just a bit, then they'll become the first team since the 2007 Mets to steal 200 or more bases in a season. While the volume isn't notable in either case, the 2023 Royals and Red Sox are on pace to become the first teams in modern MLB history to have a stolen-base success rate of 90% or better.In conclusion, yes, the stolen base is back – particularly by contemporary standards. That's good news for fans who enjoy a more tactically aggressive approach, although we'll need to check back in and be sure this trend sustains over a larger sample. Also of note is that MLB this season in the Atlantic League is testing a rule limiting pitchers to a single step-off per plate appearance. In other words, the future may be even brighter for speed merchants, both actual and aspiring.
