Why do baseball teams use shift defenses?

Teams deploy shift defenses to change the geometry of the field and turn likely hits into outs. Analytics began quantifying where individual hitters send the ball, and that information lets managers place fielders where the ball is most likely to fall. Tom Tango at Baseball Prospectus analyzed how shifts affect batting outcomes and concluded that aligning defenders to hitters' tendencies reduces the batting average on balls in play for strong pull hitters. FanGraphs and Statcast from Major League Baseball have documented how spray charts and batted-ball data made those alignments precise and repeatable across a season.

How shifts work in practice
A shift moves infielders and sometimes outfielders away from traditional positions. For a right-handed pull hitter, the shortstop may move to the right side of second base while a third baseman heads into shallow right field. That concentration of defenders covers the lane where a pulled ground ball would normally find space. The strategy does not eliminate contact but increases the probability that routine hits become outs by placing more gloves where contact is most likely.

Causes: data, specialization, and risk management
The rapid adoption of shifts grew from three linked forces. Statcast tracking and historical spray charts created reliable profiles of hitter tendencies. Analysts and front offices used that evidence to optimize defensive alignments, a process described by Kevin Goldstein and other analytics writers at FanGraphs. Pitching staffs and defensive coordinators then embraced shifts as a way to manage run prevention without changing pitching approaches. Finally, roster construction and specialization allowed teams to swap defenders situationally, so a shift could be deployed without compromising overall defense. Using available evidence to reduce opponent run production is a basic risk management decision in competitive sports.

Consequences for players, teams, and the game
Shifts changed how players are valued. Hitters who consistently pull the ball saw their outcomes decline, while those who hit to the opposite field or use the whole field gained relative value. Infielders who can cover more ground or play multiple positions became more desirable. The shifts also sparked cultural debate. Some fans and traditionalists argued that extreme defensive alignments removed action and undermined the aesthetics of baseball, while analytics advocates framed the change as a natural evolution toward optimal strategy.

Major League Baseball and the MLB Players Association addressed these tensions in the collective bargaining process. The league instituted limits on extreme shifts beginning in 2023 to restore more balanced play across the diamond. That rule change created new tactical incentives: hitters and coaches adjusted to exploit re-centered defenses, and teams re-evaluated player development priorities.

Environmental and territorial nuances matter as well. In youth and amateur leagues, shifts are less common because coaching philosophies, developmental goals, and rules often emphasize traditional positioning and skill development. International leagues vary in their use of shifts depending on scouting resources and cultural attitudes toward analytics. The overall effect of shifts has been to force a continual adaptation among hitters, defenders, and rulemakers as evidence and values interact in shaping how baseball is played.