Pitch Selection Against Ben Zobrist or, When Pitchers Adapt

I'll admit it: I've shamelessly stolen this idea from a recent Joe Posnanski blog post.  In his post, Joe goes into some depth looking at what pitchers have chosen to throw against certain hitters and notices how their pitch selections have changed over time.  Here's what he has to say about Ben Zobrist, the MLB leader in change-ups seen:

"There was a little bit of desperation in the American League in 2009, I think, as pitchers were trying to figure out HOW THE HECK to get Ben Zobrist out. I mean, in mid-June the guy was hitting .318/.429/.694. He was slugging almost .700, for crying out loud. Clearly, they were not getting Zobrist out by throwing what had been a fairly typical pattern - two-third fastballs, mix of other pitches. The advance scouts noticed that Zobrist was a big-time fastball first hitter. And so pitchers went crazy on the change-ups. Zobrist did settle down in the second half of the season ... but he was still pretty darned good. It should be fun to watch how pitchers attack him in 2010."

Just because I was curious, I figured I'd look and see exactly how pitchers chose to attack Zobrist over the course of last season.  How much of what Joe Pos says is true?  Is the change-up the key to Zobrist's undoing?

% Pitch Types Against Zobrist

So it is definitely true that pitchers changed how they attacked Zobrist, but it also appears that they couldn't make up their mind how to pitch him.  First they threw him all fastballs with bits of the other stuff; then around mid-season they threw him a lot less fastballs but threw him more cutters and change-ups; and then by the end of the season they were back to throwing him lots of fastballs, but with more change-ups mixed in than at the beginning of the season.  Of course, in June and July when pitchers were throwing Zobrist only around 44% fastballs, he still managed to put up Weighted On-Base Averages (wOBAs) of .433 and .393.

So we're dealing with very small sample sizes, for sure, but I think it's interesting to see how pitchers attempted to adapt to the emerging Zorilla and never really succeeded.  How will they attempt to throw to him this year?  Zobrist's pitch type linear weights do suggest that he's worse against change-ups than he is against any other pitch, although he still put up a positive 0.87 wCH/C last year.  I'd expect lots of change-ups again, but we'll have to see what the pitchers decide.