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Just a decade ago, stolen bases were still a somewhat prominent part of the modern game.
Today the landscape has changed. With the rise and spread of analytics, the number of stolen base attempts has declined precipitously.
The rate of steal attempts in April this year was the lowest for any April of the expansion era, which began in 1961. Analytically inclined front offices, citing run expectancy matrices and other data, have largely concluded the risk of getting thrown out isn’t worth the potential benefit in most cases.
The calculation appears to be changing. Ironically, many of the analytical trends driving today’s game have made stealing bases a more successful proposition than ever.
Runners were successful on 76.2% of stolen base attempts through May 23, on pace to become an all-time high.
There are many factors behind the uptick in success rates, but three are most commonly cited are: pitchers are no longer as adept at holding runners, shifted defenses have a harder time getting to the bag in time and catcher arm strength being deemphasized in favor of pitch-framing skills.
The most important of those is the pitcher. Whether one views stealing bases as a math equation, an art form or a combination of the two, how quick the pitcher is to the plate is the starting point for it all.
“If you’re decently fast, and we’re talking just an average major league catcher, if a (pitcher) is 1.3 seconds to the plate, that’s about right around the time you can start stealing,” said Royals second baseman Whit Merrifield, who led the American League in stolen bases in 2017 and 2018 and was leading again this season. “If he’s slower than that, then you’re going. If he’s quicker than that, you gotta find a different key to go off of.”
In Merrifield’s view, the rise in stolen base success rates can be largely attributed to a decline in pitchers’ ability to hold runners.
“I think half of it comes from a lot of pitchers not wanting to throw to bases,” he said. “Most pitchers now are pitchers from the time they’re 11 or 12 years old, and that takes away from a little bit of athleticism that you would gain from being a position player for a long time.
“It used to be where guys played all different positions for a long time, so I think pitchers used to have a little more athleticism and were better at holding runners on or throwing to bases . . . That’s not a skill that they’re as good at as they used to be.”
From a team perspective, no club has been as active on the bases as the Padres in recent years. San Diego led the majors in steals in 2020 and again leads this season through May 23, notably stealing at a rate of 78.1%.
Manager Jayce Tingler also sees a change in pitcher behavior as the catalyst for the increased success rates, while noting a change in defensive strategy plays a role as well.
“I still think the majority of stolen bases come off the pitcher,” Tingler said. “And so understanding that, there’s a lot of guys in the league who you know they’ve got really good stuff and they may go with an extra high leg kick to get more power, because they’re trying to get swing and miss. We can look for slower times. And then with shifts it can be a little bit harder to cover second base, certainly in first and third scenarios.”
The biggest measurable change, though, has been in catchers.
As the main focus of catcher defense has shifted to pitch-framing, arm strength has become a secondary consideration for many backstops. In 2015, the first year MLB Statcast data is available, there were 147 instances of a catcher recording a sub-1.9 second pop time on a throw to second base. Through the first six weeks of the 2021 season, there were six. The total sum is an environment where the opportunities for stolen bases, and aggressive baserunning in general, are ripe. And yet, most teams have been slow to take advantage of them.
Even with success rates at an all-time high, the takeoff rate—the number of stolen base attempts per estimated times on first base—is near historical lows this season.
“As a whole, stolen bases, guys are less interested in them,” Merrifield said. “All the analytics say it’s a bad thing if you get thrown out and it’s hard on guys’ bodies and they don’t want to put themselves through that.”
There is precedent for large-scale reversal in the strategy and attitudes surrounding stolen bases. From 1900 to 1925, which encompasses the Deadball Era, players ran frequently—with estimated takeoff rates upward of 10 to 15%.
From 1930 to 1964, the rate of players attempting stolen bases plummeted to levels even lower than today. From 1975 to 2000, rates spiked and again frequently topped 10%.
In today’s world of analytically driven front offices, it all comes down to the calculation changing.
Slowly but surely, it appears that it has.