All he did was defend himself. The worst part is that he knows he screwed up and he won't admit it. Just come clean. What do you want him to say? "You know, I really thought Pierre was good, I didn't realize he was a bum, my bad." He can't say stuff like that, have you ever heard a manager take accountability midseason? That'd be like a player saying, "you know, I just don't think we have the talent this year." No one's going to do that. Yep, not a good idea to go negative. Might as well call it a season, if he says, "I screwed up."