Scott Dann, Jeffrey Schlupp, Yohan Cabaye and Luka Milivojevic are doubtful to face West Brom on Saturday.
The quartet have been nursing niggling injuries and did not train on Thursday.
Schlupp, Cabaye and Milivojevic started in the midweek draw with Brighton, while Dann was an unused substitute.
Eagles boss Roy Hodgson said: “We will have to wait until Friday because it's a short turn around on this occasion so it's only the second day after we played on Tuesday evening.
“There's one or two players that we will need to further assess so we will wait until tomorrow to be 100 per cent sure on those players who are suffering a little bit from the effects of the game against Brighton.
“I don't know that any of them are massive concerns but because three or four of them didn't train and are having some sort of treatment, it's better to wait until Friday to make any judgements.
“Scott Dann didn't train on Thursday, Jeffrey Schlupp was away, Cabaye didn't train, Luka didn't train.”
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