CHARLOTTE, N.C. -- One of the first things Thomas Davis did when he returned from a four-game suspension on Monday was show teammates his abs, the outside linebacker's way of showing he's been staying in shape.

"He had about a two-pack," joked Carolina Panthers cornerback Captain Munnerlyn, who has the locker next to Davis. "He swore he had a six-pack, [but] he had about a two-pack."

The 35-year-old Davis also had a lot of pent-up energy between the time off for violating the NFL's policy on performance-enhancing drugs and the death of his father on Saturday. He grabbed Munnerlyn by the shoulder so hard that Munnerlyn had to remind he'd just played a game on Sunday.

"The Washington Redskins can get ready, because I know that first [time] when somebody touches the ball he's going to wanna go full throttle," Munnerlyn said of Sunday's game.

Yes, Davis has been missed by the Panthers as much as he has missed the team in terms of the leadership and energy he brings on the field and in the locker room. Coach Ron Rivera arrived at his news conference wearing a black T-shirt with an image of Davis, his arms and head thrown back like he'd just made a sack, and the words "I'm back."

Davis didn't speak to reporters on Monday. He'll save that for Wednesday after he has had a couple of days to process his return.

But after his father died following a somewhat lengthy illness, Davis posted on social media that the time away during the suspension has been "the toughest 4 weeks of my life."

"It's one thing to lose the opportunity to play the game you love, but to lose a parent is extremely hard!" Davis wrote. "Today God called my dad home to be with him. I want to thank everyone who has reached out to check on me and my family in the last month! Please cherish every day that you have with your loved ones because you never know when that day is going to come that you can no longer tell them how much you love and appreciate them."

The Panthers also are expected to get tight end Greg Olsen back for Sunday's 1 p.m. game. The three-time Pro Bowl selection re-fractured the right foot that sidelined him for nine games last year in the first quarter of the opener.

So the Panthers basically have gotten to 3-1 with two of their best players and leaders out of the mix.

"I didn't get a T-shirt," Olsen quipped. "How quickly you are forgotten."

Olsen wasn't forgotten, but he has been in the stadium, in meetings and around teammates on the practice field. Davis was banned until he arrived this morning, with middle linebacker Luke Kuechly the first to greet him with a huge smile.

"I think he was the first guy in the building this morning," Olsen said. "He thought meetings were at six. It's great to have him back. His energy, not only on the field but just what he brings in general is awesome."

Rivera admitted the energy and emotion Davis brings has been missing at times defensively. Carolina gave up 432 yards to a struggling New York Giants offense in Sunday's 33-31 victory that came down to a successful 63-yard field goal by Graham Gano with one second left.

Cincinnati had 396 yards of total offense the week before.

"He's got a different energy level than most players," Rivera said. "It's above the norm. Even in practice. It's kind of a little running joke between he and I. It's nice to have normal, calm practices. It's going to be a little different. So I've got to adjust myself to him."

Rivera said "winning covers up a lot" of the mistakes Carolina has made in all three phases of the game the first quarter of the season.

Davis covers a lot of ground to clean up many of those mistakes. According to the team, he is Carolina's all-time leader in tackles with 1,174. His ability to stop the run, pressure the quarterback and cover tight ends and receivers makes him one of the best all-around linebackers in the league.

So his return should bolster the defense immediately.

"Thomas is always good for about three or four explosive plays, minimum," Rivera said "They bring energy to us. That's one of the beneficial things about having a guy like that, who has that ability to take it to the next level and make something happen."

Outside linebacker Shaq Thompson has played well in Davis' absence. He is third on the team in tackles with 22, including a sack and one tackle for a loss.

But Davis brings an intensity that neither Thompson nor anybody else can.

"We missed Thomas everywhere ... on the practice field, in the locker room," defensive coordinator Eric Washington said. "When he's removed from the building you feel the impact, you feel the void.

"You don't replace Thomas Davis."

David Mayo, whose role increased at linebacker with Davis out, said the Carolina defense can't help but be better with Davis back.

"He's been working out and taking care of his body, so he's going to come in with his hair is on fire and making a lot of plays," he said.

Rivera said the Panthers will monitor Davis' snaps at first and gradually work him back to playing a close to a full game based on conditioning. The plan is to back off Davis' snaps from past seasons to make sure he's as impactful for the stretch run.

Davis already has backed off his decision to retire following this season, saying during training camp that because of the suspension he wants to play beyond 2018.

Those types of decisions by management and Davis will become more clear after the season.

What was clear on Monday was that Davis is happy to be back and everybody is happy to have him back.

"That first tackle he makes against Washington I expect him to bring everything he owns," Munnerlyn said. "I'm expecting him to be on fire. But I want him to be smart, because I don't want him to miss anymore time."