Dolphins tailback Patrick Cobbs suffered what appears to be a serious knee injury during Monday night's 31-27 victory over the Jets.
Cobbs, a utility back and core special teams contributor for the Dolphins, suffered the injury midway through the fourth quarter when he fell awkwardly after running an end around in the Wildcat offense.
Jets linebacker Bryan Thomas slung him to the ground for a 1-yard loss.
Cobbs, who has gained 36 yards on six carries and caught three passes for 23 yards this season, left Land Shark Stadium on crutches with his injured knee in a brace.
He's expected to undergo an MRI on Tuesday morning to determine the severity of his knee injury.
If Cobbs is out for an extended period of time, the Dolphins will have to find another kickoff returner. Cobbs has primarily handled that role this season, averaging 22.6 yards on his 16 kickoff returns.
The Dolphins have four tailbacks on the 53-man roster, the others being starter Ronnie Brown, veteran Ricky Williams and Lex Hilliard, who is in his second season.