The Shift

A defensive positioning strategy where infielders move well away from their traditional spots, often stacking three infielders on one side of second base, based on data showing exactly where a specific hitter tends to put the ball in play. A hard-pulling left-handed hitter might see the shortstop and third baseman both shifted onto the right side of the infield, taking away the ground balls that hitter usually produces. MLB restricted the extreme version of the shift starting in 2023, requiring two infielders on each side of second base, specifically because the tactic had gotten so effective at neutralizing certain hitters that it was reducing balls in play and, by extension, offense across the league. The rule change was a rare case of a governing body directly legislating against a purely data-driven tactical innovation because it was working too well for the game's own good. MLB.com has full coverage of the rule change and its statistical impact.