Leyton Orient skipper Stephen Dawson faces up to six weeks on the sidelines with ligament damage in his ankle.
The Irish midfielder suffered the knock during the first half of Orient's 4-1 defeat at Carlisle on Saturday.
The Os fear Dawson, who struggled with ankle problems early in the season, could miss as many as seven League One matches with the problem.
"He is out for a good period of time," said manager Russell Slade after the match.
Dawson, 26, will be out of contract at the end of the season and had been linked with Crystal Palace, Millwall and Charlton.