I mentioned during spring training that the Texas Rangers' Colby Lewis, returning to the United States after two years in Japan, was a big sleeper of mine, and I backed that up by buying him for less than $5 in each of two AL-only experts' auctions (Tout Wars and LABR, the League of Alternative Baseball Reality).
He hasn't disappointed me thus far.
After surgery for a torn rotator cuff in 2004, Lewis had to make a long transition from just a thrower who relied on a fastball that once hit the mid-90s, to more of a pitcher, a process he refined with two years as a starter for the Hiroshima Carp.
There are stark differences between the hurler we see now, and the one I last saw in the Oakland Athletics' organization in 2007. His delivery is more compact and repeatable, and because his release point is far more consistent, he has better command of all of his pitches, especially with his 90-92 mph fastball, which he's now able to spot on both sides of the plate.