Colchester midfielder John-Joe O'Toole has undergone surgery in a bid to cure a groin injury, but may return in two weeks.
O'Toole, who missed a significant part of last season after sustaining a cruciate ligament injury, has been out of action since October.
The Us had hoped that the former Republic of Ireland Under-21 international would be back in action by now but it is unlikely he will return before December.
Physio Tony Flynn told the club's official website: "Initially, the problem settled down with some rest but as soon as John-Joe stepped things up again, the problem flared up again.
"It's the same procedure that Marc Tierney and Andy Bond have undergone previously and it didn't keep either of them out for long.
"I expect John-Joe to be training again in seven to 10 days and he should be available to play again in two weeks time."