Originally Posted by REDREAD
I'm not sure what the optimal Z-swing is, but the fact that Joey is only 1 or 2 percent above average (which includes pitchers and backups) says there's room for improvement. Many of his teammates have higher rates than he does.
If Joey could increase his Z-swing percentage by 5 percent, at the expense of his O-swing percentage going up 2 percent.. I think that would be worth it.
Note, I realize that increasing the Z-swing is going to also probably increase the O-swing.
I'm not saying this isn't true, but I am not sure it is. It could easily be that the true optimal Z-swing percentage (which certainly varies hitter by hitter) could be LOWER than the league average, and that swinging at too many borderline strikes (or just not the pitch you were looking for) results in easy outs.