CHARLOTTE, N.C. -- Quarterback Cam Newton may be the face of the Carolina Panthers, but the foundation of this NFL team remains its defense.

That was made clear during the first two days of free agency.

Carolina spent the bulk of its salary-cap space on re-signing defensive end Julius Peppers and signing defensive tackle Dontari Poe and cornerback Bashaud Breeland.

Peppers, 38, got a one-year, $5 million deal that should be his last before retirement. Poe got a three-year, $27 million deal to replace free-agent loss Star Lotulelei (Buffalo) as the space-eater beside Kawann Short. Breeland got a three-year, $24 million deal to start opposite James Bradberry.

Nobody is happier than Eric Washington, who became Carolina’s third defensive coordinator in three years after Steve Wilks was named the head coach at Arizona a year after Sean McDermott went to Buffalo.

The Panthers still need a starting free safety, but that’s a position they haven’t spent big bucks in the past. Colin Jones or another young player on the roster could fill that role.

Or general manager Marty Hurney might be setting the stage to use the 24th pick of the draft on a safety. Florida State’s Derwin James and Alabama’s Minkah Fitzpatrick are strong options.

But it’s clear the emphasis in free agency was to solidify the defense that has ranked among the top 10 in the NFL in five of the past six seasons. When it fell out in 2016 was the only time in the past five seasons the Panthers didn’t make the playoffs.

Carolina still has needs offensively, most notably a backup tight end for Pro Bowler Greg Olsen and a backup quarterback for Newton. They still could re-sign Ed Dickson and Derek Anderson, who are exploring free agency.

Even if they don’t, there are options that shouldn’t cost lot. Seattle free-agent tight end Luke Willson visited with the team the past two days and remains an option. Also, former Lions tight end Eric Ebron has scheduled a visit with the Panthers on Friday, a source told ESPN’s Dianne Russini.

The Panthers filled their biggest need offensively, a wide receiver to play opposite Devin Funchess, in the trade to get Torrey Smith from Philadelphia. They’ll likely strengthen that group in the first three rounds of the draft.

But coach Ron Rivera comes from a defensive background, so it’s no surprise the team has been built around that side of the ball.

Free agency just reinforced that.