SPARTANBURG, S.C. - Panthers coach Ron Rivera learned a long time ago from defensive mentor Buddy Ryan that you'd better be able to adjust to what an offense throws at you.
That's why the Panthers are installing even more 3-4 wrinkles - three linemen and four linebackers - this season to go along with their regular base 4-3 scheme. Rivera likes the versatility it brings to a defense that finished 28th in the league in points allowed last season.
Rivera used both while working as defensive coordinator in San Diego.
"It adds a little bit of doubt in people's minds," Rivera said. "You can start with a 4-3 base and move into things and create some situations for your opponents."
And, he hopes, create turnovers. Carolina managed just 24 takeaways last season.
The Panthers planned to use more 3-4 looks last year, but a lockout-shortened offseason and some devastating injuries forced them to be fairly vanilla on defense.
"Last year we had to get very basic, very simple," Rivera said.
Defensive coordinator Sean McDermott estimates the Panthers used the 3-4 defense about 25 percent of the time in 2012.
But he hinted that number could increase this year.
It helps that defensive tackle Ron Edwards, a key space eater in the middle of the three-man line, is back after tearing his triceps last summer. The Panthers also drafted Luke Kuechly, who'd played middle linebacker along with Jon Beason in the 3-4. And the Panthers re-signed defensive end/linebacker Antwan Applewhite, whose versatility plays well in that type of scheme.
McDermott said the Panthers have the personnel to effectively run the 3-4 "in certain situations."
But they're not built to run it all of the time, in part because they don't have a true outside "Will" linebacker like Pittsburgh's James Harrison.
And that's OK.
Rivera made it clear the Panthers have no plans to make the 3-4 their base defense right now.
"No, it's an additional thing we can do," said Rivera, a former linebacker who won a Super Bowl with the Chicago Bears. "When I played for Buddy Ryan we had two defenses - one was the base defense and one was the 46. If you go into a game with just your base and they're kicking the heck out of you, what are you going to fall back on?"
For the Panthers, it will be the 3-4.
"I definitely wouldn't want to do all of 3-4 or even all of 4-3," Beason said. "I think being able to change it up throws curveballs at the offense and they can't dictate to us. We can change some things up. I think being able to play both makes us real tricky on defense."
Defensive end Charles Johnson, Carolina's highest-paid player, would see action as a pass-rushing outside linebacker in the 3-4 as he did a year ago.
He likes that idea.
"In the 3-4 you generally blitz a lot, so hopefully we can dial up a lot of blitzes and stuff out of that package," Johnson said.
The Panthers started off well in Sunday night's first training camp practice, coming up with four interceptions during 11-on-11 team drills against the offense.
NOTES: The Panthers celebrate the 20th anniversary of receiving an NFL franchise Monday. ... Carolina will find out this week whether the Jeff Otah trade will be voided. If Otah fails another physical with the New York Jets, the often-injured offensive tackle will revert back to the Panthers. ... Linebacker Thomas Davis, who's coming off three torn ACLs in the same knee, is back on the practice field and showing good speed. ... Rivera said the team's first padded practice will be Monday night.