Contreras has undeniable talent. He will pitch well as long as he can remain comfortable. I get the impression he's a bit sensitive to pressure and stress. Torre keeps reinterating that he's trying too hard; overthrrowing the ball; or thinking too much about avoiding mistakes. I saw a little of that timidness in the first inning of that game against the Reds but he was lights out once he started going after the batters.
I think he's a good pickup if you need another starter. I'm a bit of a risk taker myself so try him at your own risk.
Experience is a hard teacher. She gives the test first, the lesson afterwards.