The (Mis)-Adventures of K-Rod

Like most pitchers who come to the New York Mets after a nice run of success elsewhere, Francisco Rodriguez doesn’t throw his fastball as fast in New York as he threw it at the peak of his success:

Pitcher	Career High AVG FB MPH	Year Before Coming to NY FB MPH	First Year w/ NYM FB MPH
Francisco Rodriguez	94.8 (2006)	91.9 (MPH)	92.8 (2009)
Johan Santana	93.1 (2006)	91.7 (2007)	91.2 (2008)
Oliver Perez	93.0 (2004)	90.2 (2006)	90.5 (2007)
JJ Putz	95.6 (2006)	95.0 (2008)	93.5 (2009)
Billy Wagner	98.1 (2003)	96.9 (2005)	96.3 (2006)

 

I could make a similar chart for goal scorers coming to the Rangers, but that’s a topic for another day.

This is basically the list of Omar Minaya’s high profile pitching acquisitions as Mets GM.  Now, interestingly, all of these guys saw their velocity peak a 2-3 years before the Mets acquired them and in most cases that velocity had fallen at least somewhat in the season before the Mets pursued these players.  It’s not surprising then that for all of these guys (except Oliver Perez and K-Rod actually) their velocity continued to fall with the Mets.

Now clearly, as Metsblog.com points out this morning, K-Rod has struggled lately (7.79 ERA since July 1, 12.79 ERA in August).  What I find interesting is their suggestion that K-Rod’s loss of velocity lately is his main problem.  Unfortunately those guys didn’t make use of the wealth of data (Fangraphs, Brooksbaseball.net) available on this subject to actually tell us what K-Rod’s fastball has been doing. 

So to test Metsblog’s hypothesis, lets look at K-Rod’s fastball velocity by month in 2009 using Brooksbaseball.net’s Pitch F/X Data:

Month	Average FB MPH
April	92.9
May	92.8
June	93.0
July	92.5
August	92.1

 

A Couple of Thoughts on This Data:

• This graph on Fangraphs.com summarizes this data nicely.
• K-Rod’s fastball velocity is, in fact, trending down in July and August and he has struggled during these months.
• I’m still not certain that his velocity alone is the cause of his problems.  K-Rod’s velocity in August 2009 is still better than his average velocity during his stellar 2008 season. 
• It stands to reason that other factors beyond velocity may also be at play in causing K-Rod’s problems.

In reviewing K-Rod’s Pitch F/x Data, here’s one alternative explanation for K-Rod’s struggles – his curveball.  Here are a few facts:

• In 2008, K-Rod threw 50.4% fastballs, 27.4% curveballs, and 16% changeups.
• In 2009, he has thrown 56.3% fastballs and 12.9% curveballs, and 20.7% changeups.
• According to Fangraphs’ pitch-type linear weight data (explanation here), K-Rod’s fastball has never been a big out pitch for him. For every 100 fastballs thrown in 2009, K-Rod has saved the Mets 0.02 runs.  In 2008, K-Rod saved the Angels 0.05 runs per 100 fastballs.
• K-Rod’s out pitches have always been his changeup and curveball.
• In 2009, K-Rod has saved the Mets 4.03 runs per 100 changeups. In 2008, this number was 5.12
• Now, for the curveballs.  In 2008, 100 K-Rod curveballs saved the Angels 3.27 runs. In 2009, 100 K-Rod curveballs have COST the Mets 0.31.

My conclusion: In 2009, K-Rod has thrown fewer curveballs and he is throwing them less effectively.  This is kind of nice actually, since as Met fans we’re used to our high profile pitchers losing their fastballs.  But thus curveball business is new.  Its nice to see someone changing up that routine.