Aston Villa boss Alex McLeish says Richard Dunne could be out for at least a month after injuring his shoulder in the 1-0 defeat by Manchester City.
Defender Dunne went up for a challenge with City goalkeeper Joe Hart in the closing minutes of the match at Villa Park and landed awkwardly.
"I do believe he is going to be out for at least a month, so that's serious enough," said McLeish.
"It doesn't look good and he doesn't look too comfortable."
With Ciaran Clark also out for a period of time, after damaging knee ligaments in training on Saturday, Villa are short of cover in central defence.
Meanwhile, McLeish implored Villa's fans to support his team, despite a run of results that has seen them drop to 15th in the Premier League table.
Up to 70 disgruntled supporters gathered before the game calling for McLeish to leave the club.
"It's fashionable in the modern game and a bit of a phenomenon," said the Scotsman, formerly manager of cross-town rivals Birmingham City.
"But I'd rather they support the team if they don't fancy me. That's not under my control. What is [under my control] is getting as much as we can from the squad.
"I'm confident we can get Villa up the table again."
McLeish added that he was pleased with the effort of his players against table-topping City, despite his side losing out to a Joleon Lescott goal.
"The boys deserved something out of it, but we haven't had much luck," he said.
"The discipline of the team and the way we stuck to it was crucial to try and beat Manchester City but unfortunately we lost it on a set-piece.
"We had a chance on a set-piece but we couldn't put it in the net. That's the difference."
"I've been less than delighted with our home form but the performance level was pretty decent. Lady Luck in front of goals is eluding us but we certainly gave everything."
