Vikings coach Mike Zimmer is trying to avoid assembling what his old boss, Hall of Famer Bill Parcells, used to call a “yo-yo” team.

“Up one week, down the next,” Zimmer said Wednesday. “He wanted the same guys all the time.”

Finding that type of player isn’t easy, which is why Zimmer and General Manager Rick Spielman spend so much time interviewing players before drafting or signing them.

They’re searching for signs that suggest the kind of mental toughness needed to maneuver the arduous mental and physical grind of an NFL season.

“It’s a combination of a lot of things,” Zimmer said when asked how the team goes about trying to identify mental toughness. “You talk to a lot of their coaches. What kind of competitor is a guy? How does he handle adversity? How smart is he? Is he moody on the practice field? Does he pay attention in meetings? There’s a big combination of things that helps figure it out. How does he react when you get after him? How is the best way to coach this guy? Does he put the team first? Is he all about stats?”

The Vikings are coming off back-to-back losses for the first time this season. But their competitiveness against an elite Arizona team while missing four defensive starters indicates a strong resolve.

Sunday’s performance as favorites at home against a 5-8 Bears team will be a strong indicator as to whether Zimmer has the consistency of a playoff-caliber team or a ‘‘yo-yo’’ team.

Smith ready to push it

Free safety Harrison Smith, who has missed two of the past three games because of knee and hamstring injuries, appears ready to play Sunday.

Listed on the injury report as being limited in practice, he was back in pads and moving well during the open portion of practice Wednesday.

“I was moving around all right, so we’ll see how it keeps going,” Smith said after practice. “But it went well.”

Asked if he would be “extra careful” not to come back too soon considering he injured his hamstring two weeks ago when he came back quickly from a knee injury.

“I don’t know,” he said. “I’m not that careful. I count on other people to be careful for me, I guess.”

Injury report

Another unexpected injury has hit the Vikings defense, causing end Everson Griffen to miss Wednesday’s practice because of a shoulder problem.

Linebacker Anthony Barr (hand/groin) couldn’t practice. Barr’s groin injury forced him to miss last week’s game.

Nose tackle Linval Joseph (foot) didn’t practice, but it was an encouraging sign that he was able to jog through individual drills during open practice. He has missed the past two games. Also missing practice was defensive end Scott Crichton (concussion/neck).

Besides Smith, players limited in practice were strong safety Andrew Sendejo (knee) and linebacker Brandon Watts (rib).

Bridgewater revisits fateful final play

Quarterback Teddy Bridgewater reluctantly revisited the final play that resulted in him holding the ball too long and taking a sack, strip and lost fumble while in field goal range in the closing seconds of last week’s 23-20 loss at Arizona.

“The play call, all the receivers are coming from the left side of the field. So I tried to wait,” Bridgewater said. “I couldn’t complete the ball in the middle of the field because we didn’t have any timeouts. I had to wait until the guys got closer to the sideline to try to throw the ball. I could have thrown it over [Stefon] Diggs’ head or I could have thrown it over [Adrian Peterson’s] head a little faster. That’s one thing I could have done.”

Bridgewater said it’s not a play he can check out of based on the defense he’s seeing.

“It’s a play we hit last year against the New York Jets in a similar situation,” Bridgewater said. “So I think [Arizona was] prepared for that situation. They covered the play well. … Arizona came out in man coverage and that kind of slowed down the timing, slowed down the release of the receivers.”