With still no guarantee that Teddy Bridgewater will ever be able to return to full health, the Vikings are not expected to pick up their 2018 team option for the quarterback by the May 3 deadline to do so, according to ESPN's Adam Schefter, who cited an unnamed source.

If so, that would technically mean that 2017 is the final year of his contract.

But, as pointed out by NFL Networks' Ian Rapoport, if Bridgewater starts training camp on the physically unable to perform list, which is the expectation at this point, and is not activated from that list during the season, his contract would toll, adding another season of team control.

The Vikings did not immediately respond for comment on today's news.

Bridgewater last week joined his Vikings teammates at Winter Park for the start of the team's offseason program and he continues to rehab his surgically-repaired left knee at the practice facility. On Tuesday, General Manager Rick Spielman again praised the 24-year-old quarterback for the way he has attacked his rehab.

"[Bridgewater] has been incredible," Spielman said. "He's been in here working as hard as anyone, fighting his way back. I wouldn't put it past that kid how quickly he can comeback. But it's still unknown."

That uncertainty when it comes to Bridgewater's long-term prognosis could ultimately discourage the Vikings from picking up his expensive team option for 2018, especially if they know that he will still be under contract if he is unable to return to the lineup in 2017.

The Vikings traded back into the first round in 2014 to get Bridgewater, in part because first-round picks now come with an option for a fifth year of contractual control for the team. But those fifth-year options, which teams must exercise before the player's fourth season, are guaranteed for injury.

Last spring, the Vikings exercised their fifth-year option for defensive tackle Sharrif Floyd, a 2013 first-round pick. Floyd had knee surgery in September and remains sidelined due to complications from that surgery. When he couldn't pass a physical by the start of the league year, his $6.8 million salary for this season became guaranteed.

If something similar were to happen with Bridgewater, and he was not medically cleared by the start of the 2018 league year, the Vikings would be on the hook for a little over $12 million guaranteed.

In his report this morning for ESPN, Schefter quoted an unnamed source that said "the injury guarantee makes it tough to do." Bridgewater suffered his career-threatening knee injury last August.

On Tuesday, Spielman was asked about his cloudy quarterback situation. Coach Mike Zimmer has already declared Sam Bradford his starter in 2017. But Bradford is in the final year of his contract and the quarterback said Tuesday that the Vikings had not reached out to his agent about an extension. The Vikings, while they wait for more answers on Bridgewater, might be reluctant to commit to Bradford for the long term.

"Nothing is concrete. No decisions have been made," Spielman said Tuesday.