Sacrifice Hits Allowed occur when a ball is bunt by the hitter for the purpose of helping a runner on base progress around the bases with the batter being thrown out while the runner progressed.
More about Sacrifice Hits Allowed Leaders
Another way of describing pitching sacrifice hits allowed leaders is to say pitchers who gave up the most number of sacrifice bunts, in which one or more baserunners advanced and the batter did not safely reach base (though could have reached via a fielding error). For a pitcher, leading the league in sacrifice hits allowed should not automatically considered to be a negative; it could reflect facing teams more likely to lay down sacrifice bunts (National League pitchers are always near the top of this list as sacrifice bunts are much more common in the National League). Pitchers who are among the league leaders could also allow slightly more baserunners (thus allowing teams more opportunities to sacrifice), or it could also reflect facing teams more likely to play for a single run (thus indicating a quality pitcher who does not allow many runs).