AC Milan striker Alexandre Pato will have an anxious race against time to be fit for the UEFA Champions League return leg against Manchester United next month.
The Brazil international struck twice in Milan's 3-1 victory over Atalanta today, but hurt his right thigh and left the pitch 15 minutes from time.
"We will have to wait 24 to 48 hours before knowing the extent of the injury," said Milan vice-president Adriano Galliani.
The injury leaves coach Leonardo with a nervous wait as he prepares his side to visit Roma on Saturday before taking on United at Old Trafford on 10 March. Milan must overturn a 3-2 deficit if they are to progress to the quarter-finals of the UEFA Champions League.
"Not to have Pato would be terrible," said Galliani. "We don't have anyone who can replace him. Without him, we would need to change our tactical set-up."
Pato has been in superb form for Milan this season, scoring 12 goals in Serie A and two in the UEFA Champions League.