Crystal Palace could be without winger Yannick Bolasie and striker Connor Wickham for about a month.
The pair missed the 0-0 Boxing Day draw with Bournemouth.
Bolasie injured his leg in the build-up to the match, while Wickham hurt his calf after scoring against Stoke last weekend.
“They’re not going to play on Monday [against Swansea]. They look as though they’ll both be out for about four weeks,” Eagles boss Alan Pardew said.
“We’re pretty thin at the moment but that’s part of the game.”