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.

Miller, who broke into baseball with the Blue Jays in 2002, has been with the Marlins since 2007 as a reliever. Like most relievers, he started his professional career as a starter but made the move to the bullpen somewhere around the 2005 season. The last pitching crop of non-roster invites brought in players like Keichii Yabu, Bartolome Fortunato, and Victor Santos. Fortunato and Santos didn’t impact the major league roster but Yabu pitched better than I or anyone else probably expected.

Miller is a two-pitch pitcher when he’s working out of the bullpen. He’s your classic fastball-slider reliever. According to his FanGraphs page, he throws a fastball right around 90mph (91mph in ’07 and 89mph in ’08) and a slider at 80mph. Miller really favors his slider, throwing it 48.7% of the time in ’08. He’s been a flyball pitcher over the last two years with GB/FB rates of 0.99 and 0.72. His slider heavy workload could have had something to do with his trip to the DL with elbow inflammation in July. He was then DFA’d on August 15th.

Miller’s best season came during his first year with the Marlins in ’07. He posted a tRA* of 3.30 and in 61 IP he struck out 74 hitters. That’s good for a K% of 28.57%. The last Giants reliever to come close to a K% of 28% was Joe Nathan’s K% of 26% in ’03. In ’08 Miller saw his K% drop down to 20.90%. Over the past two years Miller has posted average walk rates — 9.2% and 9.9% in ’07 and ’08 — for a reliever in the National League. In 2008, the average reliever in the NL posted a BB% of 9.7% and a K% of 19.3%. If Miller is healthy and able to get his K% at 25% or above while maintaining an average BB% he could be a very nice pickup for the Giants.

I think one of the more appealing aspects about Miller is his control. He doesn’t have pinpoint control but in the Giants bullpen, he could look like Greg Maddux. One of the weaknesses in the Giants pen in ’08 was the base on balls. Giants relievers ranked 6th in the NL by BB% for team bullpens. The Giants have a variety of relievers with potential — Salder, Hinshaw, and Wilson — but they tend to come with control problems.

NL bullpens ranked by BB% (high to low) for ’08:

Individual Giants relievers ranked by BB% for ’08:

Sergio Romo’s control is fantastic and now that Walker is off the team, Miller could potentially be the 2nd best reliever on the team in regards to BB%. Hinshaw and Salder both have electric arms but their control could be a very real stumbling point for them in the future. Yabu, Wilson, and Taschner were just slightly worse than your league average reliever in the NL when it comes to BB%.

Overall, I like the pickup of Miller and if he could return to his ’07 numbers — presuming that he’s healthy now — he should have a good shot making the bullpen out of Spring Training. Let’s hope he’s more Yabu — with better underlying peripherals — than he is Santos or Fortunato. Miller’s upside is a repeat, or something close to, his ’07 performance but a more realistic expectation is simply a league average relief performance for the Giants in ’09. And for a bullpen that lacked any sort of consistency, league average is a step in the right direction to a better bullpen.