This isn't specifically addressed at metssuck, but it's important to realize that a trend of outperforming your peripherals is something that has to stabilize over years and years and years. At this time last year, Ubaldo was having a season for the ages, and he finished up with a 3.60 ERA. There is really no reason to believe that Lannan is going to be much better than his peripherals this year. He's walking batters at a career-high rate and has been pretty lucky in stranding runners on the basepaths. His groundball rate, while high, is not absurdly so--he's not going to receive a huge boost from it. His BABIP is around his career average at .283, and with the Nats' defense that might be sustainable, but I wouldn't lay any money on it. And in a year where strikeouts are at a record high, Lannan is barely striking out five per nine innings. People have been studying Lannan for a long time to see if there's something in his pitch selection, or movement, or groundballing tendencies, that might lead to his beating his peripherals (like they have with Cain, Hudson, Rivera, etc.) and nobody has found anything.
I'd love to believe in Lannan, I really would. I'd love to believe that he's doing something magical that makes him a better pitcher than he appears on paper. But the overwhelming body of evidence suggests that it's luck.