Cardiff City are waiting to discover the extent of a thigh injury to forward Anthony Pilkington.
He left during the second half of Cardiff's 2-0 Championship defeat by Leeds on Saturday.
The 28-year-old's injury will be assessed "over the next couple of days".
"We're hoping it's nothing too serious. He pulled up quite sharply and it didn't look too good," said Cardiff head coach Paul Trollope.
"He's a big player for us and him and Rickie [Lambert] were building some good understanding.
"We're hoping it's not too bad."
Pilkington has become an influential player for Cardiff since joining from Norwich in 2014.
The Republic of Ireland international spent the majority of his career as a winger but was moved into a central attacking role last season, where he scored nine goals.
Cardiff hope Pilkington will be fit for their trip to Rotherham on Saturday, 24 September.