Tom Savage was injured during the loss at Arlington on Thursday night.
The quarterback left the game with 7:15 remaining, after he was hit on 3rd-and-13.
Ryan Mallett played in place of Savage on the team's final series.
Following the defeat, head coach Bill O'Brien said he didn't know what Savage's injury was, or the severity of it.
"I'm not a doctor, I have no idea," O'Brien said. "I'll know better probably at some point tomorrow."
The second-year signal caller completed 18-of-29 passes for 135 yards, tossing two touchdowns and one interception.