Sunday, July 20, 2008

First Half Value: Pitchers

I'm back with the second part of my first half team value breakdown with an analysis of the pitching staff. This one should be easy, right? We have ERA which already gives us our number of runs allowed, so all we need to do is compare that to the average to get a runs above average estimate.


ERA = pitching + defense. We've already attempted to account for defense in an earlier post, so now we want to attempt to isolate the pitching component. So how do we do that? We use a defensive-independent pitching metric, in this case FIP (Fielding Independent Pitching), a metric that relies solely on those things a pitcher has great control over (K, BB, HR). Lucky for us, FIP is both

a) readily available and
b) scaled to "look like" ERA

So that's nice. Now what we'll do is park adjusment to account for OPACY playing as a slight hitters' park. Luckily, Baseball Reference does that already, telling us that the park adjusted league average ERA for pitchers who play half of their games in OPACY is 4.22 rather than 4.14. What we'll also do is adjust this to scale to Runs Allowed rather than Earned Runs Allowed (as ER vs R is often an arbitrary and nonsensical decision) by adding 0.46 (lgRA - lgERA) to our FIP values. We'll also break this down into starters and relievers; starters have an average park adjusted RA of 4.75 this season while relievers have an average park adjusted RA of 4.24.

Finally, we'll use this equation to convert our numbers into an estimate of runs above or below average for each pitcher:

RAA = ((lgFIPR - FIPR)/9)*IP

where lgFIPR is FIP, adjusted to scale to RA, adjusted for park, and customized for each player based on his mix of starting and relief innings. FIPR is each player's FIP scaled to RA.

Now onto results. Warning: Not for the faint of heart.

Bradford 5.00
Johnson 3.98
CabreraF 1.17
Guthrie 0.90
Castillo -0.01
Cormier -0.16
Bierd -0.64
Sherrill -1.20
McCrory -1.35
Albers -3.23
Bukvich -3.34
Sarfate -3.45
Walker -4.65
Burres -6.69
Olson -6.70
Loewen -7.41
Aquino -9.05
Liz -11.11
CabreraD -13.55
Trachsel -15.25

Oh that's not good. No that isn't good at all.

From a defense-independent perspective, Chad Bradford and Jim Johnson are leading the way, while Jeremy Guthrie is barely above average in 135 IP so far this season. The rest of the team have somewhat obscene values on the negative side of the ledger.

First let's talk about Guthrie. Simply, his peripherals have lagged behind his ERA for two seasons now. His strikeout rate is around average, he gives up a below-average number of walks, and he allows homers at a clip that rates as a bit above average. The key for Guthrie is that he has been much better (.652 OPSA) with runners on base than he has been with the bases empty (.722 OPSA). His BABIP is also low, sitting at .272 for a second straight year, which is interesting now that the sample is about 1300 PA. So, the book here is that Guthrie is stilly likely to regress, but then given that we're working with a decent sample of data here, it's also possible that his peripherals are underrating his true talent.

Either way, there isn't really a ton of dispute about Guthrie being an above average starter, which does have a lot of value, especially when accompanied by a price tag of less than $1MM. On the other hand, the rest of the starters on the team have been absolutely abysmal. Daniel Cabrera has put together some good results so far, but his collapsing strikeout rate and not-so-improved command means he's having a very poor season. Olson and Liz, the two young guys in the rotation, have both been awful, which has to be very discouraging.

Still worse, bullpen guys like Albers and Sarfate that have been fairly successful this season don't fare out too well under this analysis. Albers doesn't get enough strikeouts and Sarfate walks way too many hitters. The result? Both have contributed below average performances.

All told, the pitching staff comes in at an amazing 70+ runs below average. You could just look at the team-by-team FIP numbers and tell that the Orioles weren't going to rate favorably as they are the worst team in the AL in FIP, by a fair margin. So we'll see how this shakes out in a few months. I suspect the analysis will be similar, in which case we'll go back to our annual topic of overhauling the entire staff.

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