From the estimable Joe Lemire's look at the Edwin Jackson deal, this little tidbit:
Rizzo also said on the conference call that Washington believes Jackson had a flaw in his full wind-up that allowed hitters to see the ball particularly well out of his hand, according to the Washington Post.
Indeed, last year Jackson had an anomalous season in which he was far worse with no one on base (when he'd use the full wind-up) than with runners on (when he'd pitch out of the stretch).
In 2011 Jackson allowed a .339 average, .390 on-base percentage and .478 slugging percentage with the bases empty, effectively turning every hitter into someone slightly better than Texas' MVP candidate Michael Young (whose batting line last year was .338/.380/.474).
With at least one runner on base, however, Jackson shut down opponents, allowing a meager .239/.292/.373 batting line, effectively turning hitters into someone slightly worse than A's catcher Kurt Suzuki (.237/.301/.385).
It's always odd when some team thinks they've spotted something that none of the other teams were able to spot. But these things do happen sometimes. And considering that Jackson's performance has never quite matched his supposed potential, maybe this "flaw" is what convinced the Nationals to spend an extra $5 million for what looks like a fairly minor upgrade over John Lannan (assuming that he's traded).
Let's remember to keep an eye on Jackson's splits this season, but I will note in passing that Jackson's splits were perfectly normal in 2010; also, doesn't Scott Boras pay people good money to notice stuff like this?
My guess is that Jackson's flaw is mostly in Mike Rizzo's head. But maybe Edwin Jackson corrects his flaw and suddenly becomes a Cy Young candidate. Odder things have happened.