CHARLOTTE, N.C. -- Carolina Panthers coach Ron Rivera in essence bet on himself when he took over the defensive playcalling late in 2018 in an attempt to save the season and potentially his job.

He'll do that again in 2019.

The plan is for Rivera to continue calling the defensive plays and for Eric Washington to remain the defensive coordinator with a focus on the defensive front and game planning.

The organization's biggest concern this offseason, not counting the sore right shoulder of quarterback Cam Newton, is returning the defense to the top-10 level it was for five of the previous six seasons.

If Newton returns 100 percent and the offense continues to progress under Norv Turner, the defense that ranked 15th in 2018 could determine the success of the 2019 season.

A third losing season in four years would put Rivera and his staff's future in jeopardy. He is taking no chances and entrusting his experience as a defensive coordinator at Chicago and San Diego to right the ship.

"The reason we were hired is there are certain things we did," Rivera recently told the Panthers' team website. "You have to stick to your specialty to give yourself the best chance."

Reading between the lines, Rivera feels the best chance for the Panthers to succeed defensively is for him to call the plays instead of Washington.

So does owner David Tepper.

"If you look through the season you look at the strengths and the weaknesses, we probably should have done some things earlier on defense when it appeared we had some problems," said Tepper, referring to Rivera taking over four games into a seven-game losing streak after a 6-2 start. "And some of those problems probably were coach-related problems and changes were made. Now they could have been made earlier. We didn't make them earlier. So that was bad."

But Tepper saw a lot of good in what happened after Rivera took over.

"A vast improvement in the defenses gives you hope we have the right personnel in there," Tepper said of the future. "As I said when I got in here [as the owner in July], a perception I still think is right ... Ron is a very good defensive coach and he has on the reigns again. That's the way it should be."

Rivera believes Washington still can be a good defensive coordinator, which is why his job title wasn't stripped along with the playcalling.

"My whole attitude is still making sure I'm training and helping Eric to grow," Rivera said. "He's a terrific coordinator in terms of mapping things out, and with a little more experience he can be a very good playcaller as well."

Understanding that, let's look at how the defense fared with Washington calling the plays versus Rivera.

The biggest difference was in points allowed. The Panthers gave up 25.5 points a game in 12 games under Washington and 19.0 in four games under Rivera.

One could argue that is skewed a bit since New Orleans didn't play starters Drew Brees and Alvin Kamara in the regular-season finale, a 33-14 Carolina win that snapped a seven-game losing streak. But remember, under Rivera, the Panthers also held the Saints to 12 points in a 12-9 loss at home.

In terms of total yards allowed, opponents averaged 353.7 yards a game under Rivera, compared to 353 yards a game under Washington. That's a wash.

What Rivera has to focus on is shoring up the run defense. Opponents averaged 162.3 yards rushing a game under him, compared to 96.2 a game under Washington.

In terms of third down, a weakness for the Panthers all season, there wasn't much difference. Opponents were successful on 40.4 percent of their conversions under Washington, 38 percent under Rivera.

Forcing turnovers was almost a wash as well. The Panthers forced 1.75 per game with Rivera calling plays and 1.33 under Washington. The Panthers actually fared better in sacks under Washington, averaging 2.4 per game to 1.5 under Rivera.

Rivera's biggest adjustment was to simplify, one of his staples as a coordinator.

"When he was at Chicago, we ran two or three or four defenses a game and we played them well," Hall of Fame linebacker Brian Urlacher, who played under Rivera at Chicago, told ESPN.com when Rivera first took over the playcalling. "We played them fast and didn't make mistakes."

That players trust and respect Rivera and his instincts as a playcaller works to the head coach's advantage. That respect is a big reason players didn't quit on Rivera during the losing streak that left the Panthers with a 7-9 record.

"At the end of the day, I feel comfortable with who I am and who I've become," Rivera said the day after the season ended. "I'll continue to work hard and do things I'm trying to do, and that's to win football games."