So, Chris wanted to know whether Barry Zito’s pop-up ability is something he’s maintained as a Giant, or whether he’s mostly a product of Oakland’s generous foul territory. So here’s the simple graph of Zito’s pop-ups per flyball over his career.
With the A’s he averaged 28.1%, and with the Giants he averaged 25.5%. So, there’s a clear drop-off, but on the other hand he’s never had a single below average season in this regard. It’s not entirely clear whether his decline is park-related or just degradation in skills. It seems to me like the Giants years in which his stuff was slightly sharper (2009 and 2010) also featured a rebound in his pop-up rate.
The question came up as to whether this a bankable skill or not. I’m inclined to think that inducing pop-ups is not really big part of the pitcher’s game. Zito, after all, has gotten more pop-ups (per flyball) above the average than any other pitcher. Given that, it has still taken him nine seasons to accumulate 100 extra pop-ups. And even that has really only lead to (probably) about 30 extra outs. That’s close to the extra outs that Tim Lincecum’s strikeout ability gets him per season!
The moral of the story that I see is this. Pitchers DO have the ability to induce weak contact at the major league level in lots of different ways. But these abilities are not usually enough to allow a pitcher succeed without having skills in the three DIPS categories of strikeouts, walks and homeruns. I also think that these weak-contact abilities are usually correlated with DIPS types skills, but that’s a story for another day.