The Tennessee Titans will be without their starting quarterback in Week 17. 

Marcus Mariota suffered a stinger during last week's victory over Washington, and according to a report from's Chris Mortensen, that injury will prevent Mariota from starting against the Indianapolis Colts on Sunday. Instead, backup Blaine Gabbert will make the start in his place. 

Mariota is officially listed as questionable and reportedly will test his arm in pregame warm-ups. But one source told ESPN that an independent spine specialist has warned the Titans that further damage would put Mariota's ability to throw the football at significant risk beyond this weekend.

Mortensen further reported that "one source said that it is the physical contact of a football game that would subject Mariota to the risk of permanent damage, according to the opinion of the independent spine specialist that has been shared with team officials and the medical staff."

That sounds pretty serious, and like the kind of thing that could potentially affect the Titans beyond this season. Mortensen's report indicates that the team is hopeful the nerve trauma will diminish with rest and that he can potentially play in the postseason if the Titans win on Sunday, but that would seem pretty dangerous, given the balance of the report. 

Stream all of Sunday's games on fuboTV, try it for free, and stream the CBS games on CBS All Access.  

Mariota has been injured frequently throughout his NFL career, missing six games prior to this year and playing injured in several others. He also sustained multiple injuries earlier this season that affect his ability to throw the ball, having sat out Week 2 and only appearing in Week 3 after Gabbert suffered an injury early in that game. 

The Titans picked up Mariota's fifth-year option last offseason, and his salary is guaranteed for injury. That means he could potentially be on the team's books for $20.9 million next season, fully guaranteed. If he is medically cleared prior to the guarantee date the Titans could elect to move on, and given his up and down performance throughout his career, perhaps that would be wise. But they would be left without any plan at quarterback, and it would be uncharacteristic for a team to give up on a former No. 2 overall pick who has shown upside at times and would be coming off a potential playoff season.