The Minnesota Vikings are unlikely to pick up quarterback Teddy Bridgewater's fifth-year option by the May 2 deadline, league sources told ESPN.

The Vikings could still re-sign Bridgewater, but they do not appear willing to guarantee his 2018 salary for at least $11 million for injury when the quarterback is still trying to make it back from a catastrophic knee injury that has derailed other NFL players' careers.

"The injury guarantee makes it tough to do," said one source on the Vikings' decision about whether to pick up the fifth-year option.

Bridgewater, a 2014 first-round pick, missed all of the 2016 season after tearing his ACL and dislocating his left knee during preseason practice. The injury led the Vikings to trade for quarterback Sam Bradford, who set an NFL single-season record by completing 71.6 percent of his passes.

Vikings general manager Rick Spielman said Bridgewater has been hard at work during the first week of offseason workouts.

"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 come back," Spielman said. "But it's still unknown. You know, Bradford was here the very first day and leading the group, and we are very fortunate to have both of those players at that position on our roster right now."