They said it...
"He hit 96 mph here, and flashed both a plus change with split-like action and a plus curveball. Mejia is more of a thrower than a pitcher right now, and he's still very inconsistent. However, he's just 20, so he has time to mature. The stuff is there to be a top starter as he learns to command all of his offerings."
Jason Grey, ESPN.com - November 17, 2009
"Mejia's fastball sat from 93-96 mph and touched 98, he also threw a plus changeup that looked more like a two-seamer at 85-87. It should be noted, though: the latter pitch was a little inconsistent. His curveball was even less consistent, but he threw one very sharp one for a called third strike at 78 mph, with good depth and clear two-plane break. He comes from a slot just below 3/4 and needs to focus on staying on top of the ball. He missed a chunk of the second half with a strained finger, which could impact how he grips the ball even now. He has a strong, thick build. The velocity comes easily, and if his command is better than what he showed on Wednesday and he can snap off that good curveball more frequently, he's a potential No. 1 or No. 2 starter."
Keith Law, ESPN.com - October 16, 2009