Panthers cite ‘critical mistakes’ to explain secondary woes. Problems might be deeper.

Critical mistakes, critical mistakes, critical mistakes.

That’s what a 30-27 Week 12 loss to the Seattle Seahawks came down to, head coach Ron Rivera said Monday.

“If you really go back and look at it, that’s what the game came down to and everybody says it,” he said. “Football, winning football games, comes down to four, five, six plays. And that’s exactly what got us. I’m not going to sit here and try to make any excuse other than the fact that those are things that we have to get corrected.”

Critical mistakes have been the thorn in Carolina’s side for the duration of a three-game losing streak, and perhaps none has been repeated more than the explosive passing plays allowed by the secondary.

Sunday, huge Seattle passing plays killed Carolina in a game that, because of early red zone issues, was already closer than it should have been.

Rookie starting cornerback Donte Jackson left the game in the first quarter with a quadriceps injury, and the Panthers turned to second-year corner Corn Elder and veteran nickelback Captain Munnerlyn to replace him.

Bradberry, the team’s No. 1 corner, started well with a sack off a corner blitz and a pass breakup, but then gave up a massive 54-yard gain on third down and 12 in the third quarter.

From there, Seattle had four more passing plays of more than 20 yards against Carolina, and a sixth for 19 yards.

And in the three-game losing streak, Carolina has given up 10 passing plays of 20-plus yards. Six of those plays have been on third or fourth down.

Some, such as the 35-yard touchdown pass against Elder or the 43-yard Tyler Lockett catch against Munnerlyn that set up the game-winning field goal on Sunday, have had a crucial impact on the outcome of a game.

Carolina is 1-4 on the road this season and now faces a two-game away stretch, plus four more matchups against NFC South quarterbacks in the Panthers’ final five games.

Twelve games into the season, explosive plays should not be happening in such magnitude. The Panthers are running out of time to find a solution — and maybe the right personnel, too.

Staff changes?

Rivera indicated on Monday that part of fixing the critical errors is looking inward and implementing the necessary changes.

“Maybe we need to look at some of the things we have them do,” he said. “Maybe it’s on us. ... And that’s what we do. We go up, we look at what we did. If it’s working, we want to continue to improve on it. If it’s not working, we get rid of it and find something else that does.”

But he did not seem to entertain the idea that staff changes are needed immediately, and it would be uncharacteristic of his tenure in Carolina to fire someone mid-season.

Rivera, when asked whether he’s comfortable with the assistants, said he is.

“Again, I think we’ve got a group of young guys that we’re coaching up at every position, and they’re going through a development right now,” he said. “I think that’s the thing that we have to look at. ... It’s about game experience.”

That could very well pertain to his defensive staff, too.

Defensive coordinator Eric Washington is in his first year in the position, and his position coaches are all in their first year as well. Defensive line coach Brady Hoke was hired to fill the role left vacant by Washington, who held the job for eight seasons. Linebackers coach Steve Russ is also in his first year in the job after former coach Al Holcomb joined former defensive coordinator Steve Wilks in Arizona.

Rivera also promoted former California teammate and longtime Panthers assistant Richard Rodgers to the secondary coach position after former coach Curtis Fuller resigned amid an investigation of inappropriate behavior. Assistant secondary coach Jeff Imamura, who is in charge of nickelbacks and cornerbacks, is also in his first year in the position and second year with the team.

But the Panthers have less of an excuse for why they seemed so hamstrung at corner when Jackson left the game.

Washington said missing Jackson did not force the Panthers to adjust defensively.

“The next man is expected to step up, and to execute the exact same way that the person that goes out there first (does),” he said Monday. “It was unfortunate to lose Donte. We’re anxious to get him back. We have a lot of confidence in Corn and Captain. ... And we expect them to execute with the exact same detail that the starter would.”

Jackson said in the locker room Monday that he felt “all right,” but offered no official updates on his quad. Neither did Rivera nor Washington. Jackson’s status will likely be uncertain for most of the week, and Carolina has counted on Jackson’s durability.

But if he can’t play, have the Panthers made the right moves to ensure that, if needed, their “next man up” the ideal man for the job?

Lack of depth

Carolina entered training camp with veterans Ross Cockrell and Kevon Seymour on the roster, but both went on injured reserve before the first week of the regular season.

The Panthers kept one less defensive back than normal when they made their original 53-man roster cuts, in part because they liked their group of wideouts and in part because they needed depth for a battered offensive line.

With Jackson healthy and Bradberry playing well up to the trade deadline, the Panthers did not make any moves to shore up their cornerback depth. And even if someone had been available, Carolina was extremely limited in cap space at the time.

But four months after Cockrell and Seymour went on injured reserve, the Panthers needed a depth player on Sunday against Seattle.

Elder, who might not have made the original roster if not for injuries, was their guy. His inexperience showed.

And long-term, sticking Munnerlyn on the outside when Carolina relies so heavily on its nickel package isn’t ideal, either. Carolina had to shift into their big-nickel package when Munnerlyn played on the outside on Sunday, with linebacker Shaq Thompson in coverage.

The Panthers have Lorenzo Doss, who was excellent during training camp, on the practice squad. With four NFC South matchups remaining on the schedule, Doss fits the speed profile of the type of corner Carolina wants to use to complement Bradberry and counter the speed and versatility of the Nos. 2 and 3 receivers on each team in the division.

If Damiere Byrd, who left Sunday’s game with an arm injury, faces a personal worst-case scenario and has to miss time, a logical move could be to place him on injured reserve and promote Doss, who knows the Panthers’ system.

But would he be better or more versatile than Elder?

Carolina likes that Elder can play on the outside, or in the nickel as depth for Munnerlyn.

Rivera said that Elder has competed well in practices and showed the staff his skill set. When Rivera was asked if he is comfortable with the depth in the secondary or if he felt the team needed to make a move, he said, “Well, for the most part, we’ll see. I like who he is. I like how hard he works. And I like how smart he is.”

When pressed on any potential personnel moves a few minutes later, Rivera doubled down.

“We’ll continue to stay the course.”