Sheffield United have confirmed Nick Montgomery will be out for two months with medial ligament damage.
The 27-year-old midfielder picked up the injury in Saturday's 1-1 draw with Doncaster at Bramall Lane, although Blades manager Kevin Blackwell initially suspected he had suffered cruciate ligament damage.
Although not as bad as first feared, Montgomery will be out of action for at least eight weeks and he adds to a growing injury list at United.
"It's still a long-term injury and Nick will be a big loss for us," said Blades assistant manager Sam Ellis.
"It will probably be early December before we see him playing for us again."
Fellow midfielders James Harper, Lee Williamson and Jamie Ward are also currently sidelined for the Blades, while key defender Matt Kilgallon is out with an ankle problem.
Derek Geary and Gary Naysmith are currently recovering from long-term injuries, while Paddy Kenny is banned until April after failing a drugs test.