A lot of people seem to be up in arms over Joe Blanton in the aftermath of yesterday's loss, in which he allowed five runs in six innings of work, bringing his season ERA to 10.45. In fact, Ryan Lawrence of the Delco Times went so far as to make the following argument on his blog (h/t to FuquaManuel for flagging this in the comments to today's links post).
To illustrate this point, here’s a game we can play. It’s called, "Name the Pitcher." We’ll use the stats from 2010.
Pitcher A: 11-10, 4.73 ERA, 1.37 WHIP (walks and hits per innings pitched), .283 opponents batting average, .807 opponents OPS, 84 strikeouts, 49 walks in 180 2/3 innings, 33 games.
Pitcher B: 9-6, 4.82 ERA, 1.42 WHIP, .291 BA, .796 OPS, 134 strikeouts, 43 walks in 175 2/3 innings, 29 games.
OK. Put down your pencils.
Pitcher A? That’s Kyle Kendrick, the sixth man in the Phillies five-man rotation.
Pitcher B? That’s Blanton.
While Blanton surely strikes out more batters than he walks, the rest of those numbers are pretty darn close, huh? Once could also argue – as long as they wore heavy armor while doing so – that Kendrick was more effective and more durable than Blanton last season (Blanton missed the first month with an oblique injury). Now, as the "armor" comment suggests, we completely expect more overreaction here, mostly because Kendrick is an easy target/whipping boy. But the point being made here is, based on last year's respective performances, the drop-off from Blanton to Kendrick is in no way equal to the drop-off from, say, Roy Oswalt to Blanton.
Now I'm sure most of you have already spotted the crucial errors in that argument, so I'm not going to bother going into it other than to say that it's all premised on the assumption that ERA is a good stat on which to base that analysis. Instead, I just want to focus on Lawrence's last statement: that "the drop-off from Blanton to Kendrick is in no way equal to the drop-off from, say, Roy Oswalt to Blanton." In reality, not only is the dropoff from Blanton to Kendrick much bigger than the dropoff from Oswalt to Blanton, but there might not even be a dropoff from Oswalt to Blanton at all. In fact, there's a pretty plausible argument that there's a dropoff from Blanton to Oswalt.
It largely depends on how big of a mulligan you're willing to give to Blanton for pitching hurt early in 2010. As you may recall, Blanton pulled his oblique at the end of spring training last year and got a late start on the season. When he came back, it appeared, at least, that he had unwisely rushed his rehab. His results and his peripherals were significantly worse in his first ten starts or so than they were either in 2009 or later in 2010.
Normally, you can't just say "Player X was great if you just ignore the ten starts when he sucked." That's obviously cherry-picking facts that support your argument. There has to be an actual basis for believing that the ten sucky starts were an aberration. But an injury can be an actual basis for not counting data from games affected by the injury. If the player is injury-prone, then the injury can't just be seen as bad luck. But if the injury was more flukish, then it can. Blanton is not an injury-prone player, so if his stats from the early part of 2010 were in fact affected by his oblique, then there is a reason to discount them to some degree.
So anyway, here's how Oswalt and Blanton have compared since July 1, 2010, including postseason stats:
I don't know how to find batted ball splits, but looking at these numbers, it's obvious that the difference between the two guys' ERAs is due to a difference in HR/FB (and probably also due to a difference in BABIP).
Admittedly, that isn't a huge sample size. So then, let's take a look at the data from 2009.
So here's what I get out of all that.
Obviously, when it's all said and done, Oswalt's career will outstrip Blanton's by a wide margin. Oswalt was one of the best pitchers of the past decade. No question there. But if the question is "Which guy is better right this second?" then the answer becomes a lot less clear, because the data is trending towards Blanton with time.
In 2009, Oswalt was better than Blanton, but not by a ton. Oswalt didn't have a great year, and there was only a 0.20 differential between their xFIPs. Also, Oswalt was 31 and Blanton was 28, meaning that both guys were in or very close to their primes. Today, Blanton is 30 and still in or near his prime, but Oswalt is 33 and has likely declined ever so slightly from where he was at 31 (and will continue to decline, if only very slightly, as each day passes).
Since 2009, Oswalt has been significantly better than Blanton - but only because Blanton got off to such a bad start after recovering from his oblique strain. If you give a mulligan to Blanton for that time period, then Blanton's stats are right there with Oswalt's. Blanton actually has a better xFIP, by a very small margin.
I would still take Oswalt if forced to choose, for a few reasons. First, Oswalt tends to pitch slightly deeper into games, which gives him additional value on top of his rate stats. Second, while I'm inclined to give Blanton a mulligan for his struggles early in 2010, I don't know if I can give him 100% of a mulligan. I can't say with full confidence that his struggles were entirely due to the injury, or that his injury was entirely bad luck - I can only give him a "mostly" on both counts. Third, much of the difference between these guys' ERAs is due to a difference in HR/FB rates, and while HR/FB is mostly just a function of luck, there is some evidence that it is at least slightly controllable by pitchers as well.
But even though I would take Oswalt, the difference between the two is not huge, and reasonable minds could come to a different conclusion. Unlike with a comparison between Blanton and Kendrick, where only an unreasonable mind would consider the latter even to be in the same ballpark.