Mariota (elbow) entered Sunday's game against the Jaguars after Blaine Gabbert, who started the game, headed to the locker room to be evaluated for a concussion, per Jim Wyatt of the Titans' official site.
Mariota, who has been nursing an elbow injury, began the game as the team's backup, but once Gabbert was forced out of the game, Mariota took over at QB for the Titans. It remains to be seen how much his elbow injury affects his grip (and throwing), but with Tennessee only carrying two signal-callers on their active roster, the team had no choice but to turn to Mariota, even at less that 100 percent.