He followed a pretty good learning curve when he came into the league from Korea. Becoming a dominant  closer(at least during the regular season)...And then what happened?

He got traded to Boston for Hillenbrand. Was decent for the first year. But was so bad his second year that he was ran out of town. He then signed with the worse possible team for pitching, the Rockies. And posted 2 below average season for starters.

My question to you guys is: what happened to his amazing stuff? Can he recovers them and be a decent to maybe good SP or a good to great RP again? Or is he just another case of a player peaking too early?