Tyrone attacker Tommy McGuigan is a major doubt for Saturday's All-Ireland SFC quarter-final against Dublin.
McGuigan has not trained since the Ulster final win over Monaghan, due to severe swelling on a knee.
"Tommy is suffering from swelling on his knee, and he may need a little bit of work done on his knee this week," said assistant manager Tony Donnelly.
"When he trains or plays, he suffers from swelling up afterwards. In consultation with the medical people, it looks as if something would need to be done about it.
"And if he has a medical procedure done on it this week, he would be out of contention for this weekend."