Sabermetrics revolution has entered a new phase. In any case, more and more teams are employing shifts to counteract hitters who predominantly hit the ball one way or the other. The Brewers seem most in love with the move.
For decades the strategy seemed more like a novelty. When I first started watching games, on the rare occasions a team tried it announcers would recount the tactic's origins in 1946 when it was devised by Indians player-manager Lou Boudreau to psych out Ted Williams. Now, it's so common that rarely do you hear the term "Williams Shift," which BaseballReference.com says was also tried against Cy and Ken Williams, before Ted was around.
I've alway wondered why more players -- like David Ortiz -- don't try to bunt or slap the ball to the open field. It seems that a few cheap hits might force the defense to call off the shift. Part of it is probably a macho thing. And then again, nobody accused baseball players of being rocket scientists. Maybe Robert Goddard would have figured it out.