Two of the most valuable players in the National League aren't among the leading candidates for the MVP award. They haven't driven in the most runs or tallied the highest WAR and, despite possessing some of the softest hands in the game, haven't made any Web Gems. Instead, these catchers, Yadier Molina and Jonathan Lucroy, have mastered the art of making the quietest of contributions -- their finest plays, by design, go unnoticed. These silent superstars frame pitches; that is, they make borderline pitches appear better than they are. They do this by receiving pitches with a steady hand and, perhaps, discreetly pulling them into the strike zone. Their many small contributions, one strike at a time, add up to immense gains for their teams.
To find out how often each catcher has performed the magical transmutation of ball into strike, I relied on the work of Jon Roegele. He found that while the rulebook strike zone is a rectangle, the actual strike zone called by umpires is better approximated by an ellipse and that the position of this ellipse depends on whether the hitter is batting from the left or right side of the plate. Using his algorithm, we can determine which pitches are expected to be called strikes and compare our expectations to the actual calls on the field.