I don't put much stock in that. He pitched for the lead dog in the American League east. The only really tough team he ever faced in that division was Boston. Baltimore? Toronto? Pre-2008 Tampa?
TB, Toronto, and BAL were average, and Boston was top 5, in run scoring from '05 -08. That makes for a tough division. However, let's not disrespect the offenses in the NL East. Both Lannan and Wang pitched to good offenses from divisional opponents.
Here is where the other 4 AL East teams ranked in MLB from 2005 - 2008 in run scored:
2005 2006 2007 2008
Bal: 15 17 15 11
Bos: 1 9 4 3
Tam: 12 30 15 13
Tor: 8 12 17 21
What may be underrated is the quality of the NL East offenses. Perhaps that is because they faced the Nats pitching, but, for comparison, let's look at the non-Nats NL East teams in 2009 and 2008:
2009 2008
ATL 17 15
FLA 13 14
PHI 4 9
NYM 25 8
East coast baseball - where everyone is above average. To heck with flyover country.
To me, the big difference is Wang's sinker was better at preventing homers. That can't be denied. And he was doing it in a ballpark that was very tough on RHP. But looking at ERA+, which adjusts ERA for the ballpark, the difference in HR did not really reflect itself in earned runs allowed relative to other pitchers performance in those ballparks. Wang's ERA+ from '05 to '08: 105, 124, 122, 109. Lannan: '08 - 110, '09 - 108. Looks pretty darn close.
If you want to argue there is a huge difference between these two, you need to believe in things like FIP, where HR rates are very important, to see a big difference in quality (Wang - '05 - '08: 4.20, 3.91, 3.79, 3.74; Lannan - '08 - '09: 4.79, 4.70). xFIP normalizes the HR/9, so the gap disappears ( Wang ~ 4.2 consistently, Lannan '08 - 4.28, '09 - 4.79). Another measure that takes account of the quality of the batted ball in play as well as the defense independent stats that FIP accounts for is tERA. There Wang also has a clear advantage WHEN HEALTHY - Lannan ~ 5.1 for '08 & '09, Wang ~4 for '50 - '07 & 4.5 for '08). You have to believe the advanced stats are a better measure of pitching quality than ERA in order to say there is a big difference between a healthy Wang and Lannan, or else place a lot of faith in Wang's record of preventing HRs in a tough environment.
I've gone back and forth as I have been looking at this, and hope this will not cause anyone's eyes to bleed, but I think in order to say "Wang is much better than Lannan," you have to think (A) he will get back to the way he was, and (B) his skills at preventing harmful contact are more real than Lannan's. I'm not sure about either of those statements.
