The Ks have always been there, as has an excellent HR/9. The issue was the amount of walks he was giving up, which is down significantly this season. Some people take a little while to reach their potential (Cliff Lee for example - used to have horrible walk rates, now he's the best in the game) so it's not out of the question that his success is for real. Definitely worth a gamble considering his K potential. I don't follow the NL all that much so I don't know if he can stick in the Cubs' rotation, though. I remember Zam, Gorzelanny, and Cashner not being able to squeeze in earlier on.