COSTA MESA, Calif. -- Thomas Davis heard the chirping from across the field as he worked on his pass drops and cracked a smile.

"Get back in that weak middle drop!" bellowed quarterback Philip Rivers at Davis as Rivers transitioned to another drill.

It's only the start for Davis, the veteran linebacker the Los Angeles Chargers acquired in free agency this offseason, and it'll continue on Monday when he and the defense go against the offense for the first day of organized team activities. That's when Davis will face the incessant chatter of the veteran quarterback for the first time in practice.

"I was just having a little fun," Rivers said. "They've gotten the best of us when he was in Carolina. We would have a little bit of that banter in the games.

"It'll be fun in practice. I've heard he gets after it a little bit in practice, so it'll be fun to have another defensive guy."

Two of the older players in the NFL, Rivers and Davis -- 37 and 36, respectively -- are quickly bonding and finding motivation on the field during offseason work through some good-natured ribbing.

"I feel like when you're doing that, it raises your level of play because when you talk trash, you have to be competing at a high level," Davis said. "It just raises everyone's level of play, and with us being able to do that it should be fun."

Seeking a rangy run stuffer and another veteran presence on defense, the Chargers signed Davis to a two-year, $10.5 million deal, hoping he could be one of the final pieces needed for a Super Bowl run.

Davis has been one of the first to finish during conditioning drills, setting the tone for not only his position group but the entire defense.

Rivers giving Davis the business is his normal interaction with veteran defensive players, a habit dating back to linebacker Shawne Merriman during his younger years, and extending over time to players such as Eric Weddle, Dwight Freeney, Brandon Flowers, Melvin Ingram and Casey Hayward.

"It brings out the best on both sides, adds a little bit of energy to some practices that might be a little sluggish, and it's all in good fun," Rivers said. "It's all about pushing and trying to make each other better.

"He's obviously seen a lot of football. In that division that he was in, he's gone against [Saints QB] Drew [Brees], [Falcons QB] Matt Ryan and those guys. I like it, too, to learn from guys and to see what he sees, does, how he thinks. You find out about guys as players and certainly some feedback, not only having fun but communicating to hopefully help each side get a little better."

Even with three knee surgeries and various other injuries endured over a 15-year NFL career, Davis has been one of the more impressive athletes on the Chargers' defensive field, something coaches and players have noticed.

"If you saw him out here working out, you wouldn't be able to tell that he's been playing for 15 years, for sure," said center Mike Pouncey. "I'm not going to look like that in Year 15. I won't be around in Year 15."

Chargers defensive line coach Giff Smith said having Davis on the field helps not only because of his play but also because Davis' experience will rub off on the rest of the defensive unit.

"He's able to understand the game to a point where the game becomes really slow," Smith said. "And he's able to calm a young guy down, where the game's still moving kind of fast. They can kind of calm them down sometimes: 'This is what the coach is saying. Just relax, you're going to be fine right here.'

"I think Thomas is going to be huge for us. Not only is he still very athletic and can make all of the plays but, just from a leadership standpoint, it's invaluable."

Starting next week, Davis can remind Rivers that he is 0-3 against him on the field during his time with the Carolina Panthers.

"I'm definitely welcoming the difference and the change and embracing it," Davis said, when asked about being in Los Angeles. "I'm really looking forward to coming in and just being a really good player.

"So many people on the outside doubted me, the team that I was with doubted me, so I'm definitely happy the Chargers organization has given me this opportunity, and I'm not going to let them down."