TEMPE, Ariz. — Much of the Arizona Cardinals’ focus the past few weeks has been on the uncertainty at the quarterback position.

Declining performance by the defense is also a big reason the Cardinals lost four of their last six games.

In five of the last six games, the Cardinals have yielded more than 100 yards rushing. In the first 10 games, it happened once.

The Cardinals were a very good tackling team through most of the year, but that’s slipped badly over the past few weeks.

“For the last couple weeks, we haven’t been able to consistently stop the run and we’ve been giving up big plays,” safety Rashad Johnson said. “We’ve trying to say that’s not who we are, but that’s who we are right now. Until we get it fixed, that’s going to be a big problem for us.

“If we’re not motivated to put the work in this week in practice to have a conscious effort to fix those problems then we’ll have the same result next week. I hope everybody puts it in their heads and stops living off the past.”

In his weekly radio appearance Monday, general manager Steve Keim said poor tackling is often attributable to a lack of motivation. And that does seem to be the case with the Cardinals.

The defense isn’t playing with the same amount of passion it did early in the season. No one can specify a reason why. Perhaps it’s a subconscious reaction to the team losing two quarterbacks to injuries.

But now is the time when the Cardinals most need a dominating defense. Carolina, the team’s opponent in the wildcard round of the playoffs, is a strong running team with a mobile quarterback in Cam Newton.

The Seahawks and 49ers, who have beaten the Cardinals the last two weeks, have similar strengths.

With Ryan Lindley at quarterback, it’s important that the defense force turnovers and the special teams make big plays.

In the last two games, both losses, the Cardinals have not forced a turnover.

“It’s been huge,” he said. “We’re not getting any short fields, either through the return game, or turnovers. We’re having to go the length of the field too often. In these critical games, especially on the road in the playoffs, they’re going to be huge.”

NOTES: ESPN reported that the 49ers had asked the Cardinals for permission to interview defensive coordinator Todd Bowles for their head coaching position. As of Monday afternoon, however, coach Bruce Arians said the team had received no formal requests.

Bowles, who signed a contract extension with the team during the regular season, will be a popular candidate because of how well the Cardinals defense has played over the past two years. He also is one of the top minority candidates for a head coaching job.

Bowles said in October he was not planning to jump at the first opportunity.

–QB Drew Stanton is day to day, according to the team, as he tries to recover from arthroscopic knee surgery. Stanton underwent surgery on Dec. 24 and doctors found infection in the knee. The Cardinals said they are hopeful he can play against the Panthers on Saturday.

–G Jonathan Cooper missed a second consecutive game with a left wrist injury. Cooper had started the two previous games. In two seasons, the seventh overall pick in the 2013 draft has made only two starts.

–ILB Larry Foote is expected to play against the Panthers after missing the 49ers game because of a knee injury. A starter, Foote has played well this season and is a key leader on the defense.