Perking Up

I guarantee you that if I had told you that Glen Perkins would lead the bullpen with a 0.55 ERA after the first month of the season, you would respond in any of the following manners.

1. “Yeah, and the Twins will be in the AL Central cellar in May” (or any other outlandish statement that has actually come true this season)

2. “He’s due to regress, though. It’ll be above 4.50 by the All-Star break”

3. “How many innings has he pitched? Three?”

4. “Get a hold of yourself, man!” *throws water glass into my face*

However, not only has Perkins been pitching well so far, it appears as though that it may be sustainable, at least to some extent. First was one of the most obvious changes that would happen to a pitcher that had been converted from a starter into a reliever, and that is that the fastball velocity increased.

From the pitchF/X tool on the Texas Leaguers website, we see that Perkins averaged just over 90 MPH with his fastball in 2008 and 2009 (’08 is the earliest year data can be found) while pitching almost entirely as a starter. Compare that to 2010 and 2011 where he’s been mainly a reliever, and his fastball has jumped to 92 MPH. If we want to go a step further, his fastball in 2011 alone has been approaching 93 MPH.

In addition to the added velocity, it appears as though Perkins has started relying more on a 2-seam fastball rather than his 4-seamer. The following shows the types of fastballs, the percentage of total pitches thrown that were that particular fastball, and then the vertical and horizontal movement (inches) of the pitch without gravity.


4-seamer: 69%, 8.91 vertical, 8.00 horizontal*

2-seamer: 5.2%, 7.48 vertical, 7.87 horizontal


4-seamer: 49.2%, 7.82 vertical, 7.72 horizontal

2-seamer: 20.5%, 7.41 vertical, 10.12 horizontal


2-seamer: 52.5%, 7.41 vertical, 10.12 horizontal

4-seamer: 20.5%, 8.79 vertical, 7.77 horizontal

* Some pitches were labeled as just plain “fastballs” and others as “4-seam fastballs.” I lumped them together and since there was a higher percentage of “fastballs”, I calculated the weighted average between the two groups.

It’s important to note that as pitchF/X classifications have improved, almost all pitchers that throw 2-seam fastballs have seen an increase of the number of 2-seamers and decrease in 4-seamers. However, by taking a look at Perkins’ average movement for these pitches, it does indeed appear that he’s began to rely on a 2-seam fastball more often. The vertical movement hasn’t changed by much, but it seems like he’s added about 2 inches of horizontal movement.

This change in pitch selection has transformed Perkins from a fly ball pitcher to one that induces grounders. During his 2008 campaign when he appeared to have solidified himself as an option for the back of the rotation, he was only getting hitters to drive the ball into the turf 38% of the time. Compare that to the past 2+ years, where he’s consistently been at 47% or higher.

This is certainly due to the 2-seam fastball, but another pitch he’s added to his arsenal is the slider. Suggested to him back in 2008 by Rick Anderson, Perkins’ slider has gone from a pitch to toy with to perhaps his best weapon. FanGraphs also rates pitches in terms of runs to determine their effectiveness, and the site currently grades his slider at 1.13 runs above average per 100 sliders thrown. That doesn’t sound like much, but consider that most pitchers have their pitches ranking between -1 and 1 runs.

You may argue that his slider hasn’t been good every season he’s used it, but consider this. In 2008, Perkins was just learning the pitch and was throwing it less than 10% of the time. Last year (the other time it rated below average) he threw only 21.2 innings. This season, it’s rated an absurd 5.75 runs per 100 pitches above average so far. This doesn’t mean that he has the best slider in the history of baseball, but he’s been seeing plenty of success to this point. Considering it also worked for him well in 2009 (when he threw nearly 100 innings), it appears that it may be a go-to pitch for him this year. That is, when he’s not pounding the zone with low-to-mid-90s fastballs.

These changes have yielded a career high in K/9 so far. He does have an increase in his walk rate as well, but that would have to be expected when he starts adding a couple MPH to his fastball. He does have yet to give up a home run this year, but when his FIP is 2.46 and xFIP is 3.55, it certainly shows that he’s been pitching solidly out of the bullpen.

Perkins will regress eventually and his end of season ERA will most likely be closer to 3.00 than 1.00, but it does appear that he may have kept his career going with a resurgence in the ‘pen. With so many question marks entering the season and more popping up as the season as progressed, it’s nice to see one of those question marks turn into an exclamation point. A good exclamation point, of course.


One Response to “Perking Up”

  1. AW Says:

    Good post and analysis. Perkins, Kubel and Span are about the only things going right. As I mentioned the other day, Perkins very well could be an All-Star representative if his era can stay so low until the break. Scary!!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: