Spotlight on: Sixth-year Chargers linebacker Stephen Cooper, an undrafted free agent out of the University of Maine.

Why Cooper?: Last season, his first as a starter, he led the Chargers with 179 tackles. Cooper missed the Chargers' first four games this season while sitting out an NFL-mandated suspension after testing positive for a banned substance, and saw his first action of the season in Sunday's 17-10 loss to the Miami Dolphins.

You're starting: Chargers coach Norv Turner said late in the week that he wasn't sure if Cooper or his replacement, fellow inside linebacker Derek Smith, would start against Miami. Cooper, who wasn't allowed to have formal contact with the team during his suspension and hadn't practiced until this week, got the nod.

How did he do?: The 6-foot-1, 235-pound Cooper was his normal, aggressive self. Twice, his helmet flew off during collisions with Dolphins players. After the second time, late in the game, a helmetless Cooper gestured toward the Miami sideline as if to indicate: Bring it on. "Physically, I was fine," Cooper said. "Mentally, I was kind of slow out there a little bit with my reads and stuff. But … I know I'm going to get stronger and stronger as the year goes."

The stat line: Cooper was credited with eight tackles, including one for a loss. Only safety Eric Weddle, with 10, had more tackles. "He brings a different kind of energy," Chargers linebacker Antwan Applewhite said of Cooper. "He's a vocal leader, somebody who knows what he is doing out there on defense."

The aftermath: The Chargers yielded 167 rushing yards to the Dolphins, including 125 to running back Ronnie Brown. Cooper clearly wasn't happy with the loss or the Chargers' sometimes-sloppy tackling. "We didn't tackle as well as we should have," Cooper said. "We had a couple of plays in the backfield that we let get away from us. We're going to work on tackling this week and get back to playing physical football."

Teammates' take: "It's great having him back," Chargers inside linebacker Matt Wilhelm said. "I love playing next to him. He's not only my teammate, but he's a friend on and off the field. And so to have him out there, the communication … I think it stepped up a level having him out there. It's just a matter of time, hopefully, before both of us are out there full time and we are revving like we were towards the end of last season."

Final word: "That's one guy that we sorely missed," Applewhite said.