Major League Baseball has identified a problem: The game lacks movement. The league wants to see more hits, more baserunners, more action, more chaos.
MLB has also identified a culprit, a defensive system that regularly absorbs the impact of its more fearsome hitters like a tai chi master gracefully neutralizing a punch: the shift. In a typical shift, three infielders crowd into one half of the field to cover the areas where a given batter is most likely to hit the ball—almost invariably the pull side. The maneuver has a long history, famously tormenting Ted Williams, but has become more popular in the last half-decade.
MLB’s working theory is that the shift incentivizes hitting the ball in the air—over the shift and ideally over the fence—which leads to more strikeouts (from a bigger, loopier swing) and more fly balls, which are more likely to turn into outs than balls hit on the ground. So: Ban the shift, create more singles and doubles, and get more movement.
It’s a nice theory—eliminate one weird trick to fix baseball. It’s also wrong. Strikeouts, not shifts, are the real issue, and if MLB wants fewer of those, it will have to consider more drastic changes.
Though the visual of a lopsided defensive alignment still elicits remarks from fans and commentators, it now happens in nearly every game. In 2010, about 1 percent of plate appearances featured a defensive shift, often deployed only against extreme pull hitters such as Anthony Rizzo and Matt Carpenter. By last season, that number had ballooned to 22 percent.
Despite this growth, it’s difficult to find the effects of the shift in leaguewide statistics. Since 1993, batting average on balls in play (BABIP) has stayed within a narrow range from .293 to .303, with no particular trend. Despite the perception that batters are seeking to hit more fly balls, there’s been no discernible movement in fly-ball rates. There is also no obvious change in the propensity of hitters to pull the ball. There is a steady decline in hits, but the reason is that players simply aren’t leaving the batter’s box as often. The strikeout rate in 2000 was 16.5 percent, but in 2007 it began a steady upward climb. Last year, it reached 22.3 percent.
Why? Pitchers have traded stamina for velocity. Since 2002, average fastball velocity has increased from 89 miles per hour to 92.8 mph, according to Baseball Info Solutions. Managers have also increased the number of pitchers they use each game, from 3.63 per team in 2002 to 4.36 last season. Starting pitchers aren’t expected to throw as many innings and can pitch closer to the limits of their velocity for more of their time on the mound. A big reason that starters are not asked to throw as many innings is that reliever velocity has increased as well. Teams generally no longer lose pitcher quality when they swap a tired starter for a succession of live-armed relievers.
Pitchers are also using more off-speed pitches, which are more likely to induce swinging strikes. Fastballs were nearly two-thirds of pitches in 2000 but fell to 55 percent last season. As a result of these changes, the swinging strike rate was as high last season as it’s been since the metric began being tracked in 2002. It’s also possible that hitters are contributing to the trend by trading contact for power. Hard hit rate has climbed substantially in the last 20 years, as contact rate has slowly declined.
The result is that last season, leaguewide batting average shrunk to its lowest point since 1972. But it’s not because defenses are more effective: Hitter success once the ball is in play has changed little since the early ’90s. If we pretended the 5.8 percent increase in strikeouts hadn’t happened and redistributed those plate appearances using league average rates for walks, home runs, and BABIP, we suddenly recover two decades of lost baserunners. In 2018, league batting average, on-base percentage, and slugging percentage were .248/.318/.409. In our redistributed model using 2000’s strikeout levels, the numbers jump to .264/.335/.436. That’s right in line with the “steroid era,” when no one was complaining about a lack of offense.
The shift is a leak in the roof. It’s easy to spot, and the fix is straightforward. Increasing strikeout rates are mold under the floorboards: subtler, more consequential, and fixing the issue might require you to tear everything up. To reduce strikeouts, you must reduce strikes, and that cuts to the fundamentals of baseball. But there are two fairly straightforward options: Tighten the strike zone or lower the mound.
MLB has occasionally issued proclamations about how the strike zone should be called. The zone has changed shape over time, but it is also determined by umpires’ split-second decisions and decades of muscle memory. It’s hard to change that overnight. Tightening the zone, while ultimately feasible, requires ongoing feedback to umpires. It also risks that the main effect will be to trade strikeouts for walks which, one imagines, is not exactly what MLB is going for.
Lowering the mound requires none of the messy human elements of re-defining an invisible box, just a willingness to alter the physics of the game. MLB has lowered the mound before—exactly 50 years ago, after the 1968 season, causing an immediate jump in offense. A taller mound allows pitchers to gain velocity as they step downhill, and increased velocity is the most obvious correlate to the rise in strikeout rate over the last decade. Lowering the mound would likely give hitters a substantial advantage compared to today’s game. Whether that advantage manifests as more contact or more power on contact is an open question, but it’s fair to assume that offense would spike.
Banning the shift would be a narrower, more limited response to baseball’s perceived problem, but it would do something, right? After all, the mere fact that the shift has become ubiquitous indicates its effectiveness. Indeed, the shift takes a big chomp out of batting average on pulled groundballs, but eliminating the shift would have a negligible impact on the game. Jayson Stark of the Athletic, working with Sports Info Solutions, found that banning the shift would create just under three extra hits per team per month, most of which would be singles. That’s not enough to perceptibly change the game on a day-to-day basis.
If banning the shift were deemed too inconsequential, and lowering the mound too drastic, there is another path that MLB can take: Do nothing. The shift and modern pitcher usage emerged out of analysis and experimentation, and countermeasures might be discovered in the same way. Every team is incentivized to figure out how to beat today’s pitchers and defenses, and the pendulum tends to swing back on its own, given enough time.
If Stark’s article is any indication, however, the appetite within MLB is very much for doing something. Ending shifts would elevate offense for certain hitters on pulled groundballs, but as a tactic to stimulate offense, it’s the equivalent of trying to lose weight by dieting on Tuesday afternoons. There are real solutions, but they affect every single pitch. Banning the shift would mostly just change the angle from which fielders watch the batter strike out.