Yesterday, I said that the Nats rotation would clearly fall back to Earth, and I meant it. They can't have 4 of the best seasons of all-time. But how far will each pitcher fall and for that matter will tonight's pitcher Edwin Jackson pitch any better. It's time for a traipse through some fancy stats.
These are values that can vary from pitcher to pitcher but in general fall within a defined range. There can be an outlier or two in any given year but they are rare and barely fall out of the expected range. For these if any Nats are outside the range you'd have to really expect them to fall back into it.
BABIP (usually ranges from .250-.325)
Strasburg: .262 (rough, back of the envelop 2-year ave .275)
Gio: .228 (.280)
ZNN: .200 (.270)
EJax: .250 (.320)
Detwiler: .238 (.272)
This is a big one and we're gonna see some regression. I LOVE the fact that Strasburg is not far from how he's done in his past and completely in line with the usual range. The rest of the group, including E Jax unfortunately, are going to have a few more hits fall in. ZNN should feel it the worst.
HR/FB (6.0% - 13.0%)
Strasburg: 0.0% (4.5%)
Gio: 0.0% (8.5%)
ZNN: 4.2% (14%)
EJax: 5.0% (9.4%)
Detwiler: 9.1% (10.6%)
So few homers! Strasburg just doesn't give up homers. He'll give up a handful but not much more than that. Gio might be in line for a big bump backwards here. ZNN is an interesting case. He had terrible luck here 2 years ago (22%) and great luck here last year (6%). I expect some real improvement here but I'll need him to go through the whole year giving up just a couple bombs before I'll believe he's changed into a Strasburg. Dewtiler is fine.
LOB% (66% - 80%)
Strasburg: 82.5% (71%)
Gio: 80% (77.5%)
ZNN: 80.7% (73.3%)
EJax: 51.3% (72%)
Here's where Edwin has gotten screwed. He's actually gotten lucky with hits and homers, but has bad luck when guys have gotten on base. Tipping his pitches, maybe? Strasburg should get a little less lucky here but not terribly so, maybe ZNN, too. Others are pretty close.
Here what we want to see if anyone has improved enough in these stats to justify the change in results we are seeing on the field. There IS a range but it's very broad and frankly I think it's more telling to look at their stats last year. It's difficult to improve on something like BABIP or LOB%. but I like to believe you can for the below.
Strasburg: 42.9% (42%)
Gio: 52.7% (48%)
ZNN: 48.7% (44%)
EJax: 51.1% (46%)
Detwiler: 64.3% (43%)
Detwiler's GB% is a bit crazy. You have to go back to 2007 to find someone who did that well for an entire year. Can he do it? Maybe. Certainly he can be up around 60%, but given it's only been a few games, he hasn't done it before then I want to see it before I expect it. I think it's nice to see here that everyone has improved. Edwin's numbers give me pause a bit, though I'll get back to exactly why.
Strasburg: 9.00 / 2.16 (11 /2)
Gio: 10.27 / 2.66 (8/4)
ZNN: 5.33 / 0.67 (7.5 / 2.3)
EJax: 9.47 / 1.42 (7.4 / 3)
Detwiler: 8.44 / 2.25 (5.5 / 2.73)
The big things to notice here are how Gio has made big strides in both striking people out and walking fewer. Maybe it's just having that pitcher respite, but the guy looks really good here. ZNN is walking no one, 2 walks in 27 innings, while Detwiler is striking out a bunch more. Edwin has improved too - so again I'll get back to it.
What does all this mean? It means that the National pitchers are in general getting lucky AND pitching better. That makes is far less likely that we're going to see a stretch where everyone sees their ERAs bounce back close to 4.00. For Strasburg I see the least change. He's pitching how he always has. He may give up a couple more runs but honestly this is a guy that should be in the low 2.00s. Gio's numbers are exciting because even though he should be giving up a couple more runs, he's pitching much better. The more I see him the more I like him to be under 3.00 as well. ZNN has the farthest to "fall" out of any of them. A lot of his great pitching so far has been based on things going his way. Not that he's going to be terrible or anything. Based on the limited info we have so far, he should end up with a year a lot like last year and that's good. This is a damn good 1 through 3.
Detwiler and Jackson are the question marks. Detwiler IS pitching very very well. Not 0.56 ERA well but arguably better than ZNN. The question though is how much of that is a fluke of small sample size? He's so far off some of his numbers that it's hard to just buy this as improvement. Is he suddenly Brandon Webb at his peak? If we were talking about 20 starts here maybe you start to buy into it, but for now it's a situation where Ross is going to have to prove it every time out for a couple months before Nats fans can get excited about him. As for Jackson, as the most veteran arm you tend to buy into his history more than others. That makes his improvements in GB%, K/9, and BB/9 a little less believable in my eyes. And I'm not enthused by how right now he's getting a screwed by his pitching with RISP, when the Nats talked about that as a strength ("he was tipping!") and the fact that he's getting lucky in other areas. This can go a lot of ways but I don't see him developing into that #2 type guy that some people were thinking he could be. I see more just repeating last couple years of minor disappointment in the high 3s. But hey - an awesome game today could change everything.
I think the key points are
- Very early but the Nats are pitching better and getting lucky
- Should see some regression but again pitching better so they should still be among the best in the majors
- Strasburg and ZNN are as good as most expected. Gio may in fact be better.
- Detwiler is so far off his history, but we have so little history for him that we just don't know if this is real.
- Jackson's not necessarily in for a large improvement. I wouldn't bet on it but I can't rule it out either.