The Giants kicked off the free agent market this offseason by inking lefty reliever Jeremy Affeldt to a 2-year, $8M contract. The team, in sore need of bullpen help, made the first step among many in an effort to fix their battered bullpen. Affeldt definitely improves the bullpen but for fans that haven’t seen Affeldt pitch, what does he throw? How much does it break? Does he have a good fastball? What’s his story? Why should we like this signing?

These are all questions I hope to answer in this profile of Jeremy Affeldt’s 2008 season with the use of PITCHf/x data. I’ve downloaded the pitch data for every single pitch that Affeldt threw in ’08. I’ve sifted through it, looked at it, and of course, made some visual aids.

Let’s dive right in and see what I found out.

To begin things, let’s start with the basics. What does Affeldt throw when he’s coming out of the bullpen? The following table is a collection of general information of Affeldt’s offerings. I’m also following the table with a pitch selection chart for Affeldt, so it’s easier to visualize.

Pitch, number thrown, average velocity, average X-Break (horizontal), and average Z-Break (vertical)

Calling Affeldt a three-pitch reliever might be generous because in actuality he’s much closer to being a two-pitch reliever. But, Affeldt did throw three pitches last year as recorded by PITCHf/x. Affeldt’s main weapon is his fastball. 64% of his pitches were fastballs that, on average, were clocked at 94.4mph. That’s pretty good velocity for a lefty coming out of the bullpen. Only Brian Wilson of the 2008 bullpen has a faster fastball — Wilson’s average fastball was 95.8mph and several other Giants relievers (Sadler, Threets, Hinshaw) worked in the 92-93 range. Next up is the curveball, which Affeldt threw 31% of the time. The curve, on average, broke 5.52 inches vertically. For comparison, Tim Lincecum’s curveball broke a little over 4.6 inches vertically on average in ’08. The average velocity on Affeldt’s curve was a hair under 80mph at 79.1mph. The heater and the hook accounted for 95% of Affeldt’s overall pitches thrown last season. If you’re digging in against Affeldt, you’re going to get the fastball or curve. Affeldt mixed in a changeup %5 of the time. Of 1,315 total pitches thrown by Affeldt last season, he only threw the changeup in 61 times. The changeup could serve as a pitch to separate his fastball and curveball some more, in terms of speed, if Affeldt wishes to go in that direction.

We’ve seen what Affeldt is likely to throw, but when he throws it, how does the pitch move? As you probably already know, movement is everything for a pitcher. It doesn’t matter how hard you can throw if it’s straight as an arrow. Our next series of plots will answer that question. The first plot you’ll see is a vertical and horizontal plotting of Affeldt’s offerings. A quick refresher: pitches that score negative on the horizontal plot are moving in on right-handed batters. Positive scores indicate the pitch is moving away from that same right-handed batter. On the vertical plot, a negative score indicates a downward break. A positive score doesn’t mean the pitch is “breaking upward” just that gravity had less effect on that particular pitch.

On to the plot.

Affeldt’s curve — the red grouping — will break inward on RHB’s because he’s a lefty. A RHP would see his curve breaking away from a RHB. But, he’s not afraid of throwing his curveball to either RHB’s or LHB’s. Josh Kalk’s PFX webpage has Affeldt throwing his curve 27.07% of the time to RHB’s and 33.86% of the time to LHB’s. The green grouping is Affeldt’s fastball which as we learned above, is his #1 pitch. The fastball moves away from RHB’s because of Affeldt’s handedness. You’ll notice a few blue dots scattered around in Affeldt’s fastball grouping, that’s his changeup which is thrown predominately to RHB’s.

The next plots are Horizontal and Vertical Break in relation to how fast the pitch was thrown.

Affeldt gets some seperation horizontally between his curveball and fastball. Once again, the curve will break in against RHB’s and the fastball will break away from RHB’s — or in on LHB’s. The changeup is close to the FB in terms of horizontal break but velocity of about 8mph separates the two pitches.

Again, the fastball and changeup are close in terms of vertical break with the velocity of the pitches being the main difference. The changeup has about 2 more inches of vertical break than the fastball. Unsurprisingly, the curveball gets the most vertical break of 5.52 inches on average.

Finally, one of the many reasons that Affeldt had such a nice 2008 was that he pushed his strikes swinging percentage back into the double digits for the first time since his 2003 season with the Kansas City Royals. Affeldt had an above average strikes swinging percentage of 10.8% — league average for relievers is 9.5% — in 2008. He generated 119 strikes from batters swinging at a pitch and failing to make contact.

Affeldt’s curveball proves to be a very good pitch for him. He got over half his swinging strikes with it. The fastball created 34% of swinging strikes with the changeup coming up with 12%. I haven’t seen Affeldt pitch much live, but I’m willing to wager that he does a pretty good job of selling his curveball to hitters.

Thoughts

It’s no secret that once Affeldt switched to relieving full-time he’s been a better pitcher and looking at the numbers on his pitches, it’s not hard to see why. He’s got two plus-pitches in his fastball and curveball, both are his bread-and-butter. The fastball features good velocity and the curveball is separated by almost 14mph and 10 inches of vertical break from the fastball. If Affeldt does a good job of selling either pitch, it’s going to be hard for hitters to adjust and make solid contact. If the velocity doesn’t get you, then the vertical break will surely throw a wrench into the hitting process. His changeup is his third best pitch right now but I think coming to San Francisco, an organization that has had some excellent changeups in recent years, could do wonders for that pitch. Noah Lowry (back when he actually threw it), Jason Schmidt, and Tim Lincecum have all had great success with their changeups. I can’t say if it’s an organizational pitching philosophy or not, but Affeldt could be in the right place to improve that third pitch.

When you examine Affeldt in terms of “stuff” you like what you see, but when you take into context the deal that he signed for, it’s even sweeter. His contract is a low dollar commitment for a couple of years and he didn’t cost the Giants a draft pick. All great things. He might not have the pedigree of a Damaso Marte — who just recently signed for 3-years, $12M — but he could very well pitch just as good over the next two years. Affeldt’s combination of his fastball/curveball can’t be beat for the price and at the end of 2009, he could be the best reliever in the Giants bullpen. I’ve said numerous times eariler in the season that I hate overspending for relievers, but the Giants might have found themselves a bargain in Jeremy Affeldt.