Mike Pelfrey: Potential Star? A PitchFX Look, Part 2 - The "Sinker" and the Breaking Pitches


Figure 1: The movement of Mike Pelfrey's pitches this year. The square box represents the strike zone. '

Last week I started my look at the pitches of Mike Pelfrey. The article ran a little long, so I cut it short after we finished looking at the split-finger fastball. In this article, I'll discuss Pelfrey's remaining pitches and his future as a pitcher (and what the Mets should do with his contract situation).

Pelfmovements_2009-2010_mediumFigure 2: Graph of the movement of Pelfrey's pitches in 2009 and 2010.

To Read:
Vertical Spin Deflection/Movement
: The amount of inches the ball drops/"rises" as compared to how we would expect gravity to make a pitch drop. So a fastball with positive 10 vertical movement "RISES" 10 inches more than it should if gravity was the only force acting on it and a curve-ball with -10 vertical movement drops 10 inches more than a pitch thrown that is just acted on by gravity.

Horizontal Spin Deflection/Movement
: The graph is from the view of a catcher or umpire behind home plate. So a pitch that's on the left side of the graph (and has "negative horizontal movement") moves in on righties and away from lefties. A pitch that's on the right side of the graph moves in on lefties and away from righties.

Pelfrey's Fastballs

Mike Pelfrey throws two different types of fastball aside from his splitter (which despite the name, is really a changeup type pitch rather than a fastball). The movement on the pitches this year are listed below:

Pitch Type Average MPH Average Horizontal Movement Average Vertical Movement
Two-Seam Fastball* 91.86 -8.38 +6.31
Four-Seam Fastball*
91.99 -6.16 +7.11
Table 1: The Movement and Velocity of Pelfrey's two fastballs in 2010.

If you look at the table, you'll note that the two pitches are very very similar in movement. They do not form particularly distinct clusters on movement/speed graphs. This wasn't completely the case last year; if you look at Figure 2 above, you can see that Pelfrey's two fastballs were more distinct from one another in 2009. Still, this is a problem if I have to talk about the two pitches separately. I'm unable to say with a good enough degree of competence whether a good many fastballs (the dots in Figure 2 in the middle of the big circle of fastballs, where the red and orange seem to mix) are two-seam fastballs or four-seam fastballs. Thus I'm going to talk about these two pitches together, even though my tables separate the two into separate pitches.

Regardless of what type of fastball Pelfrey uses, neither one can really be described as a pure "sinker." Neither of Pelfrey's two fastballs over the last two years has managed to have as much vertical sink as many if not most pitchers who are labeled "sinkerballers." Take for instance: Derek Lowe, Tim Hudson, Brandon Webb, Joel Pineiro, Jake Westbrook, R.A. Dickey. All of these guys have fastballs that "sink" far more than Pelf's, usually by a good bit (Dickey isn't a sinkerballer, but my point still stands about his fastball). Moreover, these guys manage to hit lower in the strike zone than Pelfrey with their pitches, as you can see below:


Figures 3 and 4:
The location of Pelfrey's four-seam and two-seam fastballs in the strike zone this year against left and right handed batters. The graph is shown from a catcher's point of view and the square box represents the strike zone.
NOTE FOR READING: The more negative (more-left on the graph) a dot is on the x-axis, the farther in the pitch is on right-handed batters and away from left-handed batters. The more positive
(more-right on the graph) a dot is on the x-axis, the farther in the pitch is on left-handed batters and away from right-handed batters.

With the four-seam pitch, Pelf seems to always aim away. With the two-seam, he seems to aim inside. With neither pitch does he hit a particularly low spot (as previously mentioned). The end results of a pitch without great sink or great lower location are shown below:

Pitch Type Batter Handedness Number Thrown Swing Rate Whiff Rate Swinging Strike Rate In-Strike-Zone% GB%
4-Seam R 458 47.38% 11.98% 5.68% 71.83% 46.75%
2-Seam R 418 50.72% 8.02% 4.06% 65.31% 60.82%
4-Seam L 547 45.70% 13.20% 6.03% 68.01% 38.10%
2-Seam L 457 48.36% 10.41% 5.03% 64.77% 41.67%

Table 2: The Results of Pelfrey's Fastballs this year against Right and Left Handed Batters.
GB %: % of balls hit into play by batters that result in ground balls.
Whiff Rate: (# of Swinging Strikes)/(# of Pitches Swung at by Batters)
Swing Rate: (# of Pitches Swung at by Batters)/(Total Pitches Thrown)
Swinging Strike %: (# of Swinging Strikes)/(Total Pitches Thrown)
% In-Strike-Zone: % of Pitches in a wide (2 feet wide) strike zone.

Here once again we see the results of a "sinkerballer" whose pitches don't have great sink and doesn't keep the ball down. Against right-handed Batters, his ground ball rate isn't particularly bad; in fact his two-seam fastball has a good ground ball rate of 60.82%. Against left-handed batters, both of his fastballs are abysmal at getting ground balls (league average GB Rate is 44%). Essentially he's a sinkerballer against less than half of the batters he faces (Pelfrey sees more left-handed batters than right-handed batters).

Meanwhile the swinging strike rate isn't particularly great either (basically around average or below average for a fastball). The end result is that against left-handed batters, the fastball, his most frequently used pitch, is a poor pitch. This is probably responsible for his career xFIP against left-handed batters being above 5. By contrast, against right-handed batters, the pitch is average to above-average.

But there IS something about Pelfrey's fastball that does give it some positive value: Despite not being a good sinker, it does manage to have a below average HR/FB rate, at least this year. I haven't completely checked beyond 2009 (and we only really have 2008 data to check), but given that his HR/FB rate is a good bit below average for his career and he uses the fastball over 75% of the time for his career, I'm going to guess that this isn't complete luck, and is actual due to some property of the pitch. So this raises the pitch from bad to maybe slightly above average for a fastball.

Which is good because he uses it so often. But not good enough to make him a high quality pitcher.

Pelfrey's Breaking Stuff:

Figures 5 & 6: The locations in the strike zone of Pelfrey's Curveballs and Sliders.

A while back there was a debate (back in the Peterson era) about whether Pelfrey should throw sliders or curve balls, with the report being that Peterson had made Pelf ditch the curve for the slider. Nowadays, Pelfrey throws both pitches, but as you can tell from Figures 5 & 6, Pelfrey basically throws the slider only against right-handed batters and the curve only against left-handed batters. You'll also notice from both figures above that Pelfrey tries to go away and low with both pitches.

That said, Pelfrey doesn't throw either pitch very frequently. He most frequently throws the curveball on 0,0 counts against LHBs (17.9% of the time on 0,0 counts), but then it's usage declines greatly after that (with a slight uptick on 1,1 counts). Against RHBs, Pelf is more willing to use the slider; he'll throw it 10-18% of the time on 0-0, 0-1, 0-2, 1-1, 1-2, and 2-2 counts (basically he'll use it early in the count or as a surprise out pitch).

The results of these pitches aren't particularly great: for example, the swinging strike rates on both breaking pitches are below average (by a good bit in the case of the slider). The slider has gotten a 60% GB Rate, but this is a very small sample size.

NOTE: Despite this, you might've noticed that on FanGraphs, the curveball's run value per 100 pitches is very good. Don't be misled by this statistic. The reason for this is the small sample size, the fact that Pelfrey throws it on 0-0 counts most frequently, and a good deal of luck. It's not a great pitch.

Anyhow, to conclude: Pelfrey's breaking pitches really aren't anything special, but form an okay complement to his fastball and splitter.


Question 1: Where does Pelfrey go from here?

The answer to this question isn't easy to answer, as Pelfrey is clearly a pitcher in flux. I'm of the opinion that the split-finger fastball, despite it's ineffectiveness since May, is a step in the right direction. It's clearly a new pitch, and that's something more likely to progress in a positive manner than any of his previously developed pitches (the fastballs or his breaking pitches). As a result, I think he's at the very least a #4 starter, with the possibility of being a #3 starter if he can really figure out the split-finger's use next year.

Question 2: What should the Mets do about re-signing Pelfrey?

The answer to this question is more difficult to answer, but to do so I must first dispense with a common statement I've seen on this blog: Pelfrey is the same this year as before. This is an incorrect statement. Pelfrey's xFIP is usually the root cause of this assertion, but there are several reasons why it's wrong.

First, on the most basic level, Pelfrey has now 3 and a half seasons of outperforming (by a bit) the standard 11% HR/FB ratio, meaning xFIP is underrating him and thus might not be the best measure for him. Second, as we can see this year, Pelfrey's pitch repertoire has changed this year, so that he has even attempted to throw the fastball at a lower frequency than before. This makes him pretty much by definition NOT the same pitcher as before. Moreover, he's likely to build upon his new use of the splitter for the future.

Fortunately, there's no reason to really answer this question just yet. Pelfrey is up for arbitration, and he'll get a raise for sure. It's Pelfrey's first time in arbitration, so the Mets have control of him for at least three more years. There is no reason, with his pitch repertoire very likely to change, for the Mets to commit themselves to Pelfrey just yet, especially as we'll control him through arbitration for each of his years in his prime. The Mets should simply accept paying Pelf whatever an arbiter decides he is worth and leave a longer-term deal off the table for now.


As it stands right now, Mike Pelfrey really doesn't have anything special. His splitter has reduced in value over the last few months and his fastballs don't produce enough ground balls (particularly against lefty players) to make him a clear success in the big leagues. But the future could be bright for Pelfrey, if he could hone his splitter and maybe improve his fastball. We shall see if he can take that step. I hope that he can.

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