Rochdale's on-loan defender Ethan Ebanks-Landell is expected to be out for a month with a quad injury.
The 26-year-old has returned to parent club Wolves for treatment.
He has scored twice in eight League One games since joining in January on a loan deal until the end of the season.
"The scan has shown it is slightly more serious than we thought. They initially said he'll miss three to four weeks, but it could be longer," said Dale first team coach Brian Barry-Murphy.
Rochdale - who last week sacked long-serving manager Keith Hill - are 22nd in League One, two points from safety.