NFL Media Insider Ian Rapoport reported Tuesday, per a source who has spoken to Mettenberger, that the quarterback suffered a grade one AC joint sprain in his right (throwing) shoulder.
That put on hold Tennessee's plans to use the rest of this season to evaluate what they have in Mettenberger. He's shown flashes of athleticism in each of his five starts, making downfield plays with his strong arm for an 8.3 yards per pass mark. He's also committed his share of rookie mistakes and shown streaks of erratic decision-making.
If Mettenberger can return in time to build off his previous work, he stands a chance to convince Whisenhunt and the Titans' front office that he's starting material beyond this lost season. If he crumbles, though, Tennessee is a rock-solid bet to draft a quarterback near the top of the 2015 NFL Draft.