However, the 16-goal striker has been assessed by Forest’s medical staff and they feel the problem is not as serious as first thought.
Hart told Forest's official site: "We’ve had a good look at him today. He had a tight hamstring and we decided to take no risks whatsoever with him at Palace on Saturday.
"The problem may well be related to his back and we’re hoping that in a couple of days time he might be ok."
PALACE MATCH REPORT