CHARLOTTE, N.C. -- Defensive end Charles Johnson spends much of the Carolina Panthers' weekly media availability reading his cell phone while leaning on a large wooden trash container next to his locker.

He looks like he couldn't care less about what's going on around him.

Don't be fooled.

Coach Ron Rivera admits it's taken a while for him to get a handle on his sack leader, who is expected to play in Sunday night's NFC South clash against New Orleans after missing two games with a sprained right knee.

Carolina defenders will tell you that they've been fueled by Charles Johnson's intensity. AP Photo/Mike McCarn

Rivera referred to Johnson as an "enigma'' before last month's game against Atlanta, and he didn't mean it in a negative way.

“Sometimes you look at him and go, ‘Oh, he doesn’t care,' '' Rivera said. "Other times you look at him and go, ‘Oh boy, it means a lot to him.’ At practice, he picks his moments and he goes hard. And then he goes to the sideline and stands. He’s kind of aloof at times because he doesn’t want you to think he cares.

“Then you watch him, and he cares.”

That never was more evident than last month's Monday night game against New England in which Johnson was injured on the first series of the third quarter. He spent most of the rest of the game pacing the sidelines, trying to convince the trainers and coaches he could return.

Rivera finally put him in for the final series, and the former Georgia star immediately brought pressure to quarterback Tom Brady.

Johnson didn't want to get back on the field because he has a six-year, $72 million contract. He wanted to because he loves the game so much that he was willing to risk potentially damaging his knee further to help his team win another game.

That he's returning for the first of two games against the Saints (9-3) in a three-week period that could decide the division champion and a first-round bye in the playoffs is good news for the Panthers (9-3).

As well as they have played the past two weeks without Johnson, they'll be better suited to handle Drew Brees and the NFL's sixth-ranked offense with him.

According to ESPN Stats & Info, the Panthers give up 4.6 yards per play when Johnson is on the field, 5.6 when he's not. Even bigger, opposing quarterbacks have a rating of 33.0 when Johnson is on the field, 47.9 when he's not.

The league QBR average is 52.

"There is a little bit of savviness to the way Charles plays,'' Rivera said. "He has a good feel and a good understanding of who he is playing against. It helps us defensively.

"The young guys may fall into a trap, but Charles is a little more savvy. He's not going to fall into those things or he may anticipate something a little better.''

The Panthers also have 26 sacks when Johnson, who leads the team with 8.5, is on the field. They have only 13 when he' s not.

As Seattle showed in a 34-7 victory over the Saints on Monday night, pressure is disruptive to what New Orleans wants to do.

"It's huge,'' safety Mike Mitchell said of getting Johnson back. "We don't get better losing one of your better players. Getting him back, you do get better. He's a huge voice, not necessarily rah-rah, but his leadership he brings by the way that he plays, his attitude and intensity, you have to have it.''

Johnson is not an enigma from that standpoint. Nobody works harder to refine his craft.

"Most guys with that kind of contract don't work the way that he works,'' Mitchell said. "They don't behave the way that he behaves. He's in here every Tuesday on his off day and he's working out every day. I admire that about him.

"Shoot, Charles Johnson, seventy-million dollars, he's in here on Tuesday. I'd better be in here. He's a great role model for us.''

Don't take Mitchell's word for it. Ask one of the young players who filled in for him the past two weeks.

"Great leader,'' Frank Alexander said. "He sets the tone for how us young guys play. He's kind of like a big brother to all of us. You see a big brother doing something you want to watch his intensity.''

You don't see that intensity in the locker room. Johnson pretty much keeps to himself, answering questions when somebody stops by to ask, but otherwise keeping his nose in his cell phone.

"That's just my mentality,'' Johnson said. "I don't get into other people's business. I just keep it straight forward and work. If that's what you call an enigma, then he can call me that.''

There are a lot of teams who could use an enigma like Johnson.