Vikings coach Mike Zimmer said Monday that quarterback Sam Bradford’s left knee is feeling better, a day after it caused Bradford to miss the Vikings’ game against the Pittsburgh Steelers.

But while the Vikings will try to get Bradford ready for Sunday’s game against the Tampa Bay Buccaneers, Zimmer said he still doesn’t know when Bradford will be able to return.

“I anticipate that when he’s ready to practice and he’s ready to play, he’ll be able to play,” Zimmer said. “Honestly, I don’t have a crystal ball. I know you guys want to ask me about all these things, but I don’t have a crystal ball, so, sorry. I wish I did; I’d call some games better.”

Zimmer said he did not believe the injury would require the Vikings to sign another quarterback, adding the team is confident in Case Keenum should he need to start again Sunday. Keenum went 20-for-37 against the Steelers, throwing for 167 yards in a 26-9 loss.

Bradford had surgery to repair a torn left ACL in 2013 and 2014, and on Sunday, Zimmer said, “He’s had two surgeries on his knee; sometimes it swells up.” On Monday, though, he said he didn’t think Bradford’s knee issues had anything to do with his prior surgeries, adding he thought the quarterback twisted his knee once during the Vikings’ season-opening win against the Saints.

“It’s hard to say,” Zimmer said. “I don’t think it’s a result of the surgeries. I think he twisted it or something during the game. But I don’t think it has anything to do with the surgeries.”

An NFL Network report on Monday called Bradford’s injury a bone bruise, adding the Vikings would see how the quarterback responded to an injection this week.

Zimmer also apologized for his curt postgame news conference Sunday, during which he declined to discuss Bradford’s injury several times and said the quarterback would be “fine,” even though he could return in one week or six.

Asked Monday about that timetable, Zimmer said, “I was being facetious. Honestly, I don’t know how long [it will be]. I thought he had a chance to play Sunday, until we worked him out [before the game].

“You know, sometimes after the game, I’m upset, and I know our fans deserve better than that. But they didn’t have any wine for me in the locker room to chill out. Where I get frustrated is, I want to protect my players. I’m never going to put a player out on the field that cannot take care of himself. I don’t have a crystal ball. When he’s ready, he’s going to play. I don’t think it’s going to be a long time, but I have no idea.”

While on the subject of uncertain timetables for quarterbacks, Zimmer said he doesn’t know when Teddy Bridgewater might be able to return from the physically-unable-to-perform list, responding to an NFL Network report that claimed Bridgewater might be ready to come back by the middle of the season.

Bridgewater, who tore multiple ligaments and dislocated his left knee in August 2016, must remain on the PUP list for at least the first six weeks of the season. The Vikings then have five weeks to determine when he could begin practice, and a three-week window from his first day of practice to determine whether he should be added to the active roster.

“I know there’s reports out there he’s going to be ready in six weeks,” Zimmer said. “I have no idea.”

Keenum, who made his first start for the Vikings on Sunday, was pressured on 46.1 percent of his dropbacks, according to Pro Football Focus. The Steelers only brought more than four defenders after him six times, but they used their time-honored repertoire of zone blitzes to bring pressure from various places.

“Quite honestly, a lot of it, the protecting and the quarterback depth [in the pocket], a lot of these things go hand-in-hand,” Zimmer said. “He got deep a couple times, and we’re not protecting at that depth. Some of it was that. We were late out of the snap one time. For the most part, we got on the right guys.”