Tuesday, February 09, 2010

Oliver Perez Loss In Fastball Velocity

I am working up a big post on Oliver, but since his drop in velocity was in the news today, I figured I would excerpt the relevant portion today.

Metsblog relayed an article by Matthew Carruth over at fangraphs today pointing out that Oliver Perez was among the "leaders" in velocity lost off their fastball between 2008 in 2009. Oliver's fastball was 1.2 mph slower in 2009, which was the 15th biggest loss in baseball.

Matt Cerrone had this to say about that finding:
…i have to think that is mostly because of his knee, and not being able to get the right pivot off his front leg…
I could not agree more with this.

I am very tough on my Mets, but I think I am fair, and I feel very strongly that Ollie's struggles last year are legitimately because of injury. Sometimes a guy just sucks and blames it on injury - but I don't think that is the case here. And here is why:

In addition to having the slowest average fastball of his career (90.0, down from 91.2 the year before) his changeup velocity was UP almost five MPH. His average changeup went from 80.1 to 84.9. At that speed, there is only 5 MPH separating the changeup from the fastball -- a useless gap.

In order to be effective, a changeup has to be at least 8 to 10 miles per hour slower than the fastball.[1] For reference, the gap between Johan Santana's fastball and changeup was 11.2 MPH in his 2008 season. Oliver Perez had a 9.4 MPH gap in his successful 2007 season.

He was all out of sync, and it was something physical or mechanical - he wasn't just terrible for no reason. The excessive zip on his changeup is proof of that. If he's healthy, I think his fastball bounces back to where it used to be.

I really think Ollie can come back strong in 2010. Check back here at Fonzie Forever for more on this in the next few days.

[1] No citation on this, so someone can point me the right direction if they like. I know I've read it but I'd rather be safe than sorry before I get some random rumor floating around the interwebs.


Ari Berkowitz said...

Here are two articles on the subject one by Josh Kalk at THT and one by Dave Allen over at Baseball Analysts. http://www.hardballtimes.com/main/article/anatomy-of-a-pitch-change-up/


They shed some light on the optimal speed differential between a fastball and changeup

Brian said...

Ari, thanks so much for those! I like the Hardball Times article in particular there. Interesting that he found that a gap of up to 15 mph is still good - I figured that at that point the benefit of the changeup might diminish.

Either way, it is clear from the first article that the less the gap in the speed of the changeup, the less effective it is -- which contributed greatly to Ollie's struggles last year.

Ari Berkowitz said...

No problem, enjoy reading your blog since finding it a few weeks ago (I'm one of your subscribers!), but that's a long story. Anyways, exactly I had remembered that I read these two articles a little while back so it wasn't hard to find. If you're not familiar with Josh Kalk, I advise you to read everything he's ever written about pitching!

Santana has it at the optimal 9-11 MPH and that's where Ollie needs it to be. Perez still has to be able to locate. Batters only swung at a miniscule 39.6% of his pitches and when they aren't chasing your off-speed stuff barely has any value. So in order for Perez to get back to his '07 self, he needs to locate his pitches (most importantly his fastball and changeup) and get a 10 MPH differential between his fastball and changeup. This will make batters chase his slider out of the zone.