Quarterback Trevor Siemian exited the Jets' matchup against the Browns in the second quarter on Monday night, leaving the game following a gruesome ankle injury.
Siemian was hit by Browns defensive end Myles Garrett as he released the ball, and his left leg bent backward as he hit the turf. Siemian left the game and did not return before halftime.
Luke Falk replaced Siemian after getting called up from the Jets' practice squad. Siemian is being evaluated at halftime, the team announced.
The Northwestern product was making his first start with the Jets, as starting quarterback Sam Darnold is out for three-to-seven weeks with mononucleosis.
Siemian went 3-of-6 for three passing yards in the first half. Cleveland held a 13-3 lead entering the break at MetLife Stadium in East Rutherford, N.J.