The Vikings on Saturday activated off injured reserve Bradford, who hasn't played since October 9 because of a knee injury, and placed tight end Kyle Carter on waivers.
The Vikings waived tight end Kyle Carter to make room for Bradford.
Since taking over the starting duties for the Minnesota Vikings in Week 2 of the regular season, veteran quarterback Case Keenum has continually faced persistent questions about his long-term future with the team.
Bradford's activation does not guarantee he will be among the 46 active players Sunday, and it's unclear whether Bridgewater will continue to back up Keenum as he has been doing since Week 10 or whether the Vikings will turn to Bradford now that he is back on the active roster. The last time they dressed three QBs for a game was on November 7, 2013, while Leslie Frazier was still the head coach for a game against the Washington Redskins.
Zimmer said this week that Bradford is working his way back in with the other quarterbacks but "has a ways to go still".
According to ESPN's Courtney Cronin, Keenum, who has played on three teams in five years, got a leg up on the competition by using VR to learn the Vikings' offense.
Bradford has played in one full game this season when he torched the New Orleans Saints in Week 1 for 346 passing yards and three touchdowns.
Bridgewater on Friday wouldn't reveal who Sunday's backup will be.
Bradford started two games, including the 2017 season opener, a 29-19 win over the Saints.
Bradford, who was placed on IR on November 8 with a left knee injury, returned to practice last week and completed his fifth practice Friday.
Bradford has participated in five practices since returning January 2.
"He's getting better, not getting worse, because he's putting more work in and getting more comfortable every week in their system", Belch said.