wRC+. I always ignored his eclectic behavior, because sometimes a relaxed player is a better player under pressure. But when he told the press that he was already taking swings, and then had to tell them it was all in his mind, I honestly questioned whether or not Casas was connected to reality.
But that said, I see no doubt that he is a really good hitter. Slow, injury-prone, no glove, kind of a disconnect with reality, sure, I can but all of those. But if the stars align, and he gets 600 ABs at DH, I think he'll be a 120+ hitter.