Tom Soares is set to be sidelined for at least two months after picking up an ankle injury in Crystal Palace's 2-0 defeat at home to Southampton.
Soares fell awkwardly and now joins fellow midfielders Carl Fletcher and Ben Watson in the treatment room.
"It doesn't look very good," said Palace manager Peter Taylor.
"It could be two or three months because it looks as though he might have a little crack in his ankle.
"Losing Carl, Ben and Tom has hurt us, because they can be defensive midfielders as well as attacking ones."
Meanwhile, Taylor slammed Crystal Palace's poor display against Southampton.
Goals from Kenwyne Jones and Grzegorz Rasiak did the damage for Saints, and left Palace without a win from their last four Championship games.
Taylor is alarmed by his side's lack of confidence, but admitted that at the moment Palace did not look like returning to winning ways.
"It was not good enough," Taylor said. "At the moment, we do not look like keeping a clean sheet.
"We conceded goals at the start of each half, and we began each half poorly. We have to hold up our hands and admit that.
"People were too nervous, and they are much better players than they showed tonight.
"The players lacked confidence when they were in possession, and the passing was not good enough.
"Teams can gain and lose confidence in one match. Now, we need a result at Norwich on Saturday to get it back."
George Burley was encouraged by Southampton's performance as they recorded their first away win of the season.
Saints have only lost one of their opening seven games but, following a series of draws, Burley believes it is time for them to start moving up the table.
"We have had two difficult away fixtures - and we still can't believe we didn't win on Saturday (against Ipswich), because we were even more dominant," he said.
"This was another good away performance, and there are definite signs for optimism, because we have a good blend of youth and experience.
"This is the style I want to play. After we took an early lead here, we could have scored four or five.
"Rudi Skacel is fully fit now, and he will be a key player for us. He has a tremendous left foot."