Once again, running back Adrian Peterson has been breaking loose repeatedly this season. Unfortunately for the Vikings, the football has often been getting loose, too, when he carries it.

After fumbling once in last week’s 23-20 loss to the Cardinals, Peterson has seven fumbles, most among non-quarterbacks, losing three of them. Only two running backs have lost more.

“Of course, putting the ball on the ground is not something you want. You want to protect the ball,” Peterson said Thursday. “What’s the most important thing? To me, in my mind, it’s ball security. Unfortunate things happen, but that’s not something you want to have.”

With three games left, Peterson is in danger of matching his career high in fumbles. He fumbled nine times in 2008 and coughed up the ball six times the following season. But since then he had been pretty sure-handed before this season.

Peterson said he wished he could have back his fumble against the Cardinals, which came on a botched exchange with wide receiver Mike Wallace on a reverse.

Coach Mike Zimmer said the coaches remind Peterson to keep both hands on the ball whenever possible. But he chalked Peterson’s latest fumble up as a fluky play.

“That fumble last week was not really indicative of the fumbles that he had earlier in the year,” Zimmer said. “But we talk about [ball security] all the time.”

Joseph returns

Nose tackle Linval Joseph returned to practice Thursday. Joseph, who missed the past two games with a toe injury, was listed as a limited participant.

Safety Harrison Smith (hamstring/knee) practiced for a second straight day, albeit on a limited basis. Fellow safeties Andrew Sendejo (knee) and Robert Blanton (knee) were full participants and should be available Sunday.

Outside linebacker Anthony Barr (groin) and defensive end Everson Griffen (shoulder) were again nonparticipants. But they were spotted doing activity off to the side during the beginning of practice.

Wide receiver Charles Johnson (ankle) also missed Thursday’s practice.

Speaking of Johnson

Johnson has been targeted only two times with one catch since making that leaping 35-yard completion against the Bears that set up the game-winning field goal as time expired in the Nov. 1 win at Chicago.

Johnson, a former starter, hasn’t been targeted in the past five games. His only two snaps in Arizona were on special teams.

“I’m sure he’s probably frustrated that he’s not [playing],” Zimmer said. “But sometimes that’s just the way it goes. You’d have to talk to him about it. But he continues to work hard. He continues to do a good job in practice. He’s like everybody. When his opportunity comes, I’m sure he’ll do good.”

Turner stands by call

Offensive coordinator Norv Turner has had a week to think about his play call late in the loss to the Cardinals that resulted in a game-sealing sack and fumble by quarterback Teddy Bridgewater. And he still believes it was a good play.

“We’ve got a lot of sideline plays. This is one that’s worked for us last year, worked for us in the past,” Turner said. “The way they defended the play, if we had to do it again, we would have thrown the ball over Adrian’s head and kicked the field goal. They defended the play real well.”

On Wednesday, Bridgewater said the coaches did not allow him to check out of the play and into another one. Turner was asked about that Thursday.

“It’s a good play,” he said. “There’s no reason to check out of it.”

Robinson ‘decent’

Rookie outside linebacker Edmond Robinson made his first NFL start against the Cardinals. With Barr sidelined, he got the nod over veteran Jason Trusnik, who replaced Barr when he got reinjured in the loss to the Seahawks.

“[Robinson’s] a guy that has really stepped up and paid attention to the details,” defensive coordinator George Edwards said. “We thought that he warranted the position to give him a try there, and he played pretty decent for us there this past game.”