I watched the FLA/AZ game and I honestly have no idea where all this sinker talk is coming from. He has a straight fastball, curve, slider, and change that I saw. His outs seemed pretty equally distributed between fly, ground, and strikeout.
His control still needs a little work, as he missed his spots more often then I would've liked to see. Fortunately, the DBacks are free swingers and the home plate ump had a pretty generous strike zone (Melvin was very close to coming out to argue).
I thought his biggest advantage was the fact that he hid the ball extremely well. His curve also looked very good, and he used it as more (and more effectively) of an out pitch than his slider (which honestly was pretty nasty as well).
I would say that going forward, he's definitely a nice #5 with potential to be much more. If you have room, add him. If not, watch closely as I can't see him being around as a FA for long if he continues his improvement.
place to go for all your sig needs...