Firstly, if a player rejects a bat it was never a players bat to start with. If he uses it and then rejects it or gives it away, then it obviously didn't cut the mustard. Players keep the bats that work for them, it's tools of the trade and we do the same. They will I imagine reject bats that don't feel right, wrong weight, pickup and there may be nothing wrong with them performance wise.
What am I getting at? Simply, unless the player has told you why they rejected it treat any claim with a pinch of salt.