Vikings quarterback Teddy Bridgewater is continuing his rehab from a devastating knee injury without a set timeline, sources told the Star Tribune.

Bridgewater's availability for the 2017 season remains uncertain given the severity and time of his injury, which included a dislocated knee and multiple torn ligaments suffered during a non-contact drill in an Aug. 30 practice.

During his season-ending press conference Jan. 3, head coach Mike Zimmer said he had not been given a timetable for Bridgewater's return. Zimmer added quarterback Sam Bradford, for whom the Vikings traded a 2017 first-round pick and 2018 fourth-round pick to Philadelphia days after the injury, has "earned the right" to be the starter moving forward.

"I'm worried about Teddy getting better," Zimmer said when asked of a potential quarterback competition. "He comes in here every single day, busts his rear end and I just want him to get better right now, so we will worry about those things later."

The nature of Bridgewater's injury makes it difficult to predict if and when he'll be able to resume his football career, Zimmer said.

"With this injury that he has, it's different with everyone," Zimmer added. "They went back and, whoever has had this injury, they've studied it and the ones [who] have come back and how long it's taken to come back, how long it hasn't come back. But they're all different, there's no exact injury where they're all the same."

Due to a May deadline, the Vikings will have to make a decision on whether to exercise Bridgewater's fifth-year option before he's recovered. Otherwise Bridgewater, the 32nd-overall pick in the 2014 NFL Draft, would be a free agent after next season.

Bleacher Report reported Friday that Bridgewater would "likely miss the entire 2017 season." Star Tribune sources disputed that assertion.

Bridgewater was voted by teammates as the recipient of the Vikings' 2016 Ed Block Courage Award. Recipients from each team will be honored March 11 in Baltimore.