Bradford was eligible to practice after spending six weeks on injured reserve but was held out. He can come off the IR list and join the active roster on Jan. 3.
Bradford sustained a noncontact knee injury during Minnesota's season-opening win over New Orleans that kept him sidelined for the next three games. He briefly returned to action on Oct. 9 in Chicago, only to be pulled before the end of the first half. Bradford's lack of mobility against the Bears led to him being sacked four times; he averaged 3.27 yards on 11 throws during the game.
Bradford's availability for the playoffs will be determined at a later date. If the Vikings (12-3) beat Chicago on Sunday, they'll earn a first-round bye and begin postseason play in the divisional round.
"We'll see when he practices," Zimmer said. "All I've done is talk to him. I haven't watched him work out or do any of those things. But I think we'll get him back practicing [next] week."
Bradford threw for 346 yards, three touchdowns and no interceptions while completing 84.4 percent of his passes in his dynamic Week 1 performance. The Vikings turned to Case Keenum when Bradford couldn't complete an on-field workout before a Week 2 loss in Pittsburgh. Keenum relieved Bradford again with 25 seconds remaining in the first half at Soldier Field in Week 5 and has been the Vikings' starter ever since.
Keenum has delivered the best season of his career, throwing for 3,358 yards, 21 touchdowns and just seven interceptions. Minnesota currently has Keenum, Teddy Bridgewater and third-string quarterback Kyle Sloter; Bradford's return would bolster the Vikings' depth even further.
"It'll be great," Pro Bowl receiver Adam Thielen said. "Another leader. Another guy that has been huge in this team's success even though he hasn't been on the field. He's a guy who's in all the meeting and helping us out if he thinks there's something we can do better, and things like that. Just another leader to be out there and help this team win games."
Bradford underwent multiple tests and an arthroscopic procedure on his left knee before he was placed on IR.
"He says he feels good," Zimmer said. "He's been working out and doing things, getting on the field. He's throwing the ball and doing workouts. ... I haven't seen him work out."
Bradford will be a free agent in 2018.