From what I remember he declined a trial with us to prove his fitness. Not an unreasonable request given his injury. Plus, it says something about him that he would rather go to a club to sit on his arse than go somewhere where he will play.
He clearly holds Liverpool in very low regards. He refused a trial to prove his fitness with us, yet that's exactly what he accepted when he went to Man Utd. He has only just signed a contract so effectively he was on trial with them.