Rich Hill dominated AAA in his career, but just couldn't pitch in the majors...until about middle of last year when he suddenly found out how to face mlb hitters. And he enjoyed enormous success for a period of time. I'll put a poll up later when I get all the names. But criteria to be eligible are below
-Enjoy Success consistently in the minors
-Enjoy Failure in the majors, catastrophic isn't necessary, at least significant struggle
-Less than 150 career MLB innings
Names I have so far are Dana Eveland, Hayden Penn, Adam Loewen.