Carlos Tevez has said that the uncertainties surrounding his future could affect his performances this season.
"To play for a super club like Manchester United without any preseason work behind me is going to be a real handicap." He told the Daily Mail.
"I am a fighter and am prepared for any challenge. In my career I have demonstrated this many times.
"But this is going to be very difficult.
"I desire a swift solution and demand now that all parties arrive at an agreement because I just want to play.
"I am not responsible for all this bureaucracy.
"Mentally I am prepared for to play for United at any moment, but physically it may be more difficult the longer this goes on.
"My hope was I'd be involved in the Community Shield against Chelsea at Wembley on Sunday. That I am not is very painful."
Tevez's advisers will continue talks on Thursday to resolve the dispute over the player's registration.
If an agreement is not reached on Thursday, the 23-year-old's camp must lodge their papers to the High Court.
That is expected to make the prospect of an out-of-court settlement unlikely.