Michael Owen has been ruled out for the rest of the season.
The Manchester United striker injured a hamstring during last Sunday's 2-1 victory over Aston Villa in the Carling Cup final at Wembley, having scored United's equalising goal.
Manchester United's manager, Sir Alex Ferguson, said: "It's a bad blow – he's out for the season.
"Unfortunately it's more serious than we thought. He will be operated on on Monday morning.
"It's a terrible blow for the lad and is disappointing news for us too. He has never missed a training session all season. I think the heavy pitch at Wembley on Sunday made some contribution to it but really it is just bad luck."
Owen said: "Unfortunately the specialist says I will miss the end of the season. I have loved every minute of my first campaign with Manchester United and have already enjoyed some memorable moments.
"I am determined to come back at the start of next season in peak condition."

