I've been waiting patiently for him to get the call and I'm thrilled that he finally did. After watching him closely, he reminds me a lot of pitcher he opposed yesterday, Mark Prior. Of course I am not saying that he is Mark Prior, or that he will be, but his mechanics and stuff is Prior-esque. His delivery is a bit more jerky than Prior's, but very few have a delivery as smooth and compact as Prior. Having said that, it's clear that McCarthy generates a lot of torque on his arm and because of his thin frame, I could see some possible arm/elbow issues in the future. I'd like to see him streamline his delivery a little more to reduce stress on his arm.
His fastball topped out at about 93-94 but it appeared flat and had very little movement. As a result, some hitters, namely Neifi Perez, made solid contact. His curveball looked great. It had nice drop to it and was thrown in the mid 80's. I hear he has an excellent changeup but he didn't throw it at all yesterday. He looks like he has great control, just 1 walk with 6 k's in 5+ innings.
The question will be how long he stays up with El Duque expected back in a few weeks. His next start will be against Texas so he will be tested and we'll get a better idea of where he's at. All in all, I think he is going to be special. He seems to have exceptional poise for a 22 year old kid making his debut in Wrigley Field, in an interleage game, going against Mark Prior.