I chose Arrieta. His H/9 was the same as '13, K/9 & HR/9 were very similar to '14, and his control has been improving every year, so I'm not entirely sure he'll regress too much. Probably a little bit because this game is so unpredictable, but I don't think it's going to be a drastic drop off.
Im going with Matt Harvey, he had a great year last year coming back from TJ. 2nd year is when pitchers really hit their groove and Harvey was the 2nd best pitcher prior to that injury or close to it.