Houston quarterback Ryan Mallett is being evaluated for an undisclosed injury and coach Bill O'Brien says they'll know more about his status later this week.

O'Brien wouldn't say what his injury was amid reports that he has a torn pectoral muscle.

Mallett was solid in his first career start in a win over Cleveland on Nov. 16, but he routinely overthrew receivers in a loss to the Bengals on Sunday.

Mallett was listed on the injury report last week with a chest injury but did not miss practice time. Teammates say he seemed to be in pain during the game, but they didn't know what was wrong.

If he can't play Sunday against Tennessee, the Texans will likely go back to veteran Ryan Fitzpatrick, who was benched for Mallett.