The Everton loanee was limping towards the end of Saturday's 2-1 defeat by Scunthorpe and will have a scan on his ankle on Monday.
Palace are now just three points above the Iron in the relegation zone and could be without their main frontman for the run-in.
"We'll have to wait and see," said manager Dougie Freedman.
"It didn't look great. He'll have an MRI scan on Monday morning."
Source: PA
Source: PA