I am not sure exactly on the dates but I think it was last season that Miles tried to come back and the Doctors deemed his injury career ending. There is no doubt that there has been healing since those doctors made that determination. What the trainer is basing his statement on is his own ego that he is the greatest trainer in the world but also on what he is seeing Miles do today and yesterday. I also think that is what Danny is going on, what he is seeing right now. I don't think it is a stretch to say that the knee has come a long way and whatever precent you want to call it, when he steps on the court for the first time, his knee is going to be in pretty good shape (unless the trainer is totally lying and Danny was completely fooled by what he saw Miles do). The big question is how does the knee hold up to NBA work, which is much different from even hard core rehabbing. Some here seem pretty convinced that he has no chance. I just don't know and I don't even think doctors, trainers, or GM's know.
What we do know is that he has gotten to the point where he can run around on the court enough to impress one Danny Ainge. For me that is enough to believe he has a chance and it is going to be one of the fun aspects of this preseason. I am glad he is in camp. I recognize that even if he scores 7 points or whatever that he alone will not replace Posey's overall contribution. I also believe that the difficulty to replace Posey's contribution has been over-stated. All this "we wouldn't have won without Posey so therefore we will never win without him..." is just overstating the "replaceability" of Posey's contribution. He is a bench player who scored 7 points a game, played great D sometimes (not againt LeBron for example), was clutch,... We can win without Posey and it has nothing to do with Miles. We can win without Cassell and PJ too.