West Ham United striker Andy Carroll suffered a knee injury during their 0-0 draw with Southampton.
Carroll was a second-half substitute at St Mary's, where he made his return from an injury picked up in the defeat to Liverpool, but he left the stadium on crutches and said he does not know the severity of his injury.
"The sad thing for us is the injury to Andy Carroll which we can ill-afford to take with our injury problems," Allardyce said.
"It's the same knee, he got kicked in the back of the knee and felt something wrong.
"He stayed up and was a nuisance. I just hope that staying on hasn't done any more damage.
"He got fit in two and a half weeks [after Liverpool] but clearly it's going to take longer this time because it's the same injury."
