Tennessee Titans quarterback Marcus Mariota is not expected to start Sunday night against the Indianapolis Colts primarily because of a nerve condition caused by a "stinger," which has his overall playing status in jeopardy, sources familiar with his injury tell ESPN.
Mariota is officially listed as questionable and reportedly will test his arm in pre-game warmups. But one source told ESPN that an independent spine specialist has warned the Titans that further damage will put Mariota's ability to throw the football at significant risk beyond this weekend.
Blaine Gabbert is expected to start in Mariota's place, according to sources, against the Colts in a AFC South game in which the winner will advance to the playoffs and the loser will be eliminated.