Melky Cabrera. It's pretty tough to know what's going to happen here. He had WARs of 0.2,1.6, -1.1, then suddenly broke through with a 4.2 and then a 4.6 last year.
Was it all because of the PEDs? I doubt it. He was a pretty good prospect. He came up to the majors young, he played 130 games for the Yankees at age 21. Melky was pretty lousy until 2011, but then he was just getting into his prime. It isn't all that unusual for a player to start putting things together around that age.
I wonder if there is a mental part to taking PEDs? You take them and believe they are going to make you better (I mean as well as a physical aspect). It can't hurt your game to think that something is giving you an advantage. If you think you are going to be great, it can't hurt your game. I don't know what it would do to the psyche to take that away.
I'd imagine he'll work hard to prove his recent improvement didn't come out of a bottle.