Not a breakthrough post or anything, but with no game to watch tonight I decided to go in and mess around a little bit with the PITCHf/x data to see if I could identify anything wrong with our nominal go-to lefty. A couple pretty graphs in the same vein as Josh Kalk's stuff to follow. Join me on this thrilling voyage of discovery.

So far in 2008, the intended lefty-killer O'Flaherty has been anything but. Left-handed batters are currently 7-12 against O'Flaherty with a walk, two beanballs, and a 1.750 OPS. Obviously the sample is too small to mean much of anything, but considering George Sherrill only allowed 25 lefties to reach base all season last year, it's a point of concern. This bullpen can't afford to take a big step back if the team hopes to contend.

What's been the problem for O'Flaherty in the early going? I dove headfirst into his PITCHf/x numbers against lefties to see if I could find out.

I generated a pair of charts that I think should be pretty easy to understand. The first shows O'Flaherty's pitch location against lefties, split up by type (he pretty much only throws a fastball and a slider). The estimated strike zone is an approximation of that derived by John Walsh.

The second chart takes the same locations and this time splits the data up by result.

We're only dealing with six games' worth of information - I can't stress the sample size point enough - but it is worth examining these charts looking for clues. For example, based on Chart 1, you can see that O'Flaherty's trying to pitch lefties on the inner half of the plate with his fastball while dropping the slider low and away. Sherrill used to pitch away with the fastball more often, but then Sherrill's fastball doesn't break back in as much as O'Flaherty's, so where O'Flaherty would be risking doubles and homers by trying to pitch his heater away, Sherrill was only risking balls. O'Flaherty has less to lose by trying to stay inside.

The second chart shows what happened to the pitches in the first. You can see all seven hits are right there over the middle of the plate. Probably not a coincidence. The low-away stuff is still working, but O'Flaherty's been punished for coming into the middle of the zone. That's not where he wants to be hanging out.

Here's something interesting: you see that upside-down triangle of hits middle-up in Chart 2? Those three pitches were fastballs. The four called strikes surrounding them? Sliders. In fact, four of the seven hits by lefties against O'Flaherty so far have come on the fastball, even though they've been getting nearly 70% sliders. Last year the ratio was far more appropriate. Clearly, O'Flaherty's fastball hasn't been getting the job done.

At all. I looked at the numbers a little closer and, well, check them out:

It's interesting that, despite O'Flaherty's struggles, his slider has been terrific. His early swinging strike rate on the slider has doubled, and as you'd expect it's been put in play less often than a year ago. That slider has been dynamite.

But the fastball's just been putrid. Putrid. O'Flaherty's thrown it all over the place, and when he's actually managed to come over the plate, the hitters have made contact. On ~90% fewer fastballs against lefties than he threw in 2007, he's allowed just one fewer hit, and nobody's swung and missed.

The PITCHf/x numbers are too complicated and the samples are too small for there to be any smoking gun in the data, but this looks to be the heart of O'Flaherty's trouble so far. He hasn't been able to get a good feel for his fastball, and while his slider's been fine, he's had to throw the fastball often enough to get himself into trouble. When you can't consistently throw what's supposed to be your primary pitch for strikes, you're probably not going to have much success.

The good news is that O'Flaherty doesn't appear to be hurt or anything. Just wild, like a lot of other pitchers have been in the early going. However, if he keeps having to rely on the slider then he's just asking to go on the DL, so that makes two reasons why he needs to regain control of his fastball. Success and health.

You'll know that O'Flaherty's good to go when he starts spotting his fastball on the inner half and pulling his FB/SL ratio somewhere closer to 1. Until that happens, though, here's to you, RRS. You lovable son of a bitch.