Carolina Panthers coach Ron Rivera says it's time for his star players to begin stepping up Sunday when they host the Chicago Bears.

Rivera challenged quarterback Cam Newton and linebacker Luke Kuechly at a team meeting earlier this week after back-to-back blowout losses to the Pittsburgh Steelers and Baltimore Ravens.

"The thing is that we know who our guys are, and these guys have to know that we're counting on them, and I think it's important," Rivera said. "It's about being held accountable. We know they're capable of it. We can't make mistakes. They're the guys that have to be perfect."

The Panthers started off 2-0, but then lost 37-19 in Week 3 to the Steelers and 38-10 to the Ravens last week. Carolina's defense has allowed 454 yards in each of the last two games.

Rivera said he made the statements in front of the team as a way of letting Newton and Kuechly know he believed in them.

"It wasn't anything that somebody took derogatory or felt as if they were played or felt that it wasn't handled the right way," Newton said. "Coach did a great job of pointing out not only players, but plays that were unacceptable."

Said Kuechly: "I would agree with what he said. We need to play a little better."

Like the Panthers, the Bears (2-2) have dropped two straight. They are reeling after allowing Aaron Rodgers to throw for 302 yards and four touchdowns in a 38-17 loss to the Packers.

"The good thing is both teams are coming off tough losses, so it's really a get-back week for both of us," Bears linebacker Lance Briggs said. "It's not a week where we're looking at a less-threatening team."

Here are some things to watch in the Bears-Panthers game:

DEFENDING CUTLER: Bears left tackle Jermon Bushrod suffered a knee injury in practice this week and his status was uncertain for Sunday. The injury comes just as center Roberto Garza and left guard Matt Slauson appeared close to returning to action. Both have been sidelined by ankle injuries since the season opener.

Michael Ola could move to left tackle if Bushrod can't play. The good news for Ola is the Panthers could be without their top two pass rushers. Greg Hardy is on a paid leave of absence to focus on his domestic violence appeal, while Charles Johnson's status is unclear because of a lingering hamstring injury. Another Panthers defensive end, Frank Alexander, was suspended this week for an additional 10 games for violating the league's substance abuse policy again.

FORTE COULD BE KEY: Matt Forte should have a chance to put up good numbers against the Panthers, who have been gashed in the running game the last two weeks. The Bears ran for 235 yards against the Packers.

"We got it going last week, the two weeks prior to that we struggled a little bit," Cutler said. "We just need to, like everything else, stay consistent with that and keep Matt (Forte) going, he is a pivotal part of our offense."

RUNNING GAME WOES: Meanwhile, Carolina's running game is a mess. The team's top two rushers, DeAngelo Williams and Jonathan Stewart, are out, as are fullbacks Mike Tolbert and Richie Brockel. That leaves the Panthers with Fozzy Whittaker, Darrin Reaves and recently signed Chris Ogbonnaya at running back, and tight ends Brandon Williams and Ed Dickson filling in at fullback. The Panthers are 29th in the league in rushing, averaging just 3.1 yards per carry.

NEW LOOK AT CORNER: Rivera benched cornerback Melvin White this week for Josh Norman after White gave up two touchdown passes to ex-Panthers wide receiver Steve Smith last Sunday. There's a good chance Cutler will be looking to test Norman, who often plays undisciplined. Cutler is tied for the NFC lead with 10 touchdown passes, while Carolina's defense has already surrendered eight TD passes.

TIME TO UNLEASH NEWTON?: Newton hasn't been a dual threat quarterback all season due to ankle and rib injuries. He has rushed just eight times for 33 yards and no TDs. Rivera said at some point the Panthers will look to "unleash" Newton, but it's unclear if he's comfortable doing that at this time.

"You don't want to unleash him unless he's ready to be unleashed," Rivera said. "We've got to listen to what the trainers and doctors are saying, and we've got to listen to what he's telling us."

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