Monday, April 26, 2004

Lasik surgery and hitting performance

I like Matt Namee's study of the data available on players before and after Lasik surgery. He finds that the surgery appears to improve BA and SLG more than OBP.

Makes sense to me. We touched on this before with the present case of Jack Wilson. A walk is always the second-most-desirable outcome. If you give a hitter a better hitting eye, the first thing he'll do is mash more balls in an extra-base hit-worthy fashion. A hitter is looking for a pitch to hit, and hit hard, so if he is seeing more pitches he can hit hard, and hitting those pitches hard, the initial gains from improved "vision" will translate into more extra-base hits and more hard-hit outs. Meanwhile the walk rate treads water until the hitter stops seeing pitches he can hit hard.

OBP is not tied, then, to batting average - though BA is a large part of it - because new walks and new hits don't appear in equal numbers as the hitter improves. They don't grow proportionally. One reason is that some of the balls that are hit with new authority will be outs - the shortstop will jump up and spear some, the outfielders will dive to catch some, the wind will hold some in the park. Therefore OBP is not going to stay constant or steadily rise as the hitter oscillates between spells of new extra-base hitting and spells of new walking.

Given the choice of ten more walks or seven more extra-base hits, I'd guess, to a man, every MLB hitter would choose the seven extra-base hits. So, as a hitter improves, his "isolated discipline" - OBP less BA - will decline as his BA and SLG increase. The disappointment would be if the walks didn't jump in number when the extra-base hits stop coming. When the pitchers stop giving the red-hot hitter something to hit with authority, the hitter has to make them pay by drawing walks. A hitter that failed to do that would be one that gave back a temporary improvement in his batting eye.

No comments:

Post a Comment