MANKATO – Both the Vikings and linebacker Anthony Barr are frustrated.

But concerned? Not so much. Barr remains sidelined because of inflammation in his surgically repaired left knee. But Vikings coach Mike Zimmer said he expects Barr back sooner than later.

"Right now we're being careful with him," Zimmer said.

Barr had season-ending surgery on that knee last November. Barr, who had limited participation in June's mandatory minicamp, had been trying to ramp up activity during training camp, taking part in practice Sunday and Monday. But he missed practice Tuesday. Then, after the team had Wednesday off, Barr was back on the sidelines Tuesday.

"Just being smart about it," Barr said. "No need to rush it right now."

That said, there is frustration.

"I wish everything was smooth," Barr said. "Things like this, you've got to be patient. I'm just trying to be as smart as possible. There's a long time before things get serious. I want to make sure when that time comes that I'm ready."

Zimmer wouldn't rule Barr out of Sunday's preseason opener against Pittsburgh in the Hall of Fame Game, but it appears unlikely Barr will play. He has been running in the pool to stay in shape, but he will require more conditioning work on the field before playing.

"It's frustrating on his part and our part both," Zimmer said. "But it's legitimate. It's not like it's not a legitimate concern. [But] we anticipate he'll be back here pretty quick. … Right now we have to get the injury settled down and then start working on conditioning."

The ultimate goal, of course, is for Barr to be 100 percent for opening day.

"Our plan is to continue to get him ready and have him ready for Sept. 14 [at San Francisco]," Zimmer said.

Said Barr: "It's taken longer than I thought it was [going to take]. When you see your guys out here working every day, you want to be part of that."

Ready to go

Vikings running back Adrian Peterson didn't have much to say about the news that he is now off two years' probation, nine months after he pleaded no contest in Texas to recklessly injuring his 4-year-old son.

According to his attorney, Rusty Hardin, Peterson finished one-third of his probation and its terms, allowing him to apply for early termination of his probation.

"My main thing was making sure my obligations got completed, and that's what I did," Peterson said. "The early termination is what I was aiming for, and it worked out."

Peterson said he didn't want to do a public service announcement — one of the conditions of the original sentence of two years' probation that included 80 hours of community service — and also wouldn't discuss what his obligations were. "All my obligations were worked out, and I'm off," he said.

Back to work

Center John Sullivan was back in camp after missing Tuesday for the birth of his son, John Harris Sullivan, an event he called "the best moment of my entire life."

"But I'm happy to be back here and putting in the work that obviously needs to be done at this time of year," he said.

Vikings quarterback Teddy Bridgewater was asked if fatherhood had changed his center. "I don't think so," he said. "May make him a little softer. But I don't think so."

Etc.

• Zimmer was asked how long the starters would go in Sunday's game. "I don't know," he said. "I haven't decided yet. It depends on my mood."

• Peterson isn't likely to play during the preseason. So what does Bridgewater expect once the regular season starts? "He's going to be running like a caged animal that's been caged for too long," he said.