Ex-Chargers running back Mike Tolbert has agreed to terms on a four-year deal with the Panthers, a league source said Monday.

Several of the best available free-agent running backs met with teams over the weekend. Here’s a breakdown of the action.

The Panthers and LB Kenny Onatolu have agreed to terms on a three-year deal, a league source said Friday.

Former Ravens safety Haruki Nakamura has a free-agent visit scheduled with the Panthers on Thursday, according to a league source.

Geoff Hangartner was a lifesaver for the Panthers last season, providing a stablizing force on the offensive line after injuries battered Carolina’s offensive line.

The comparison has been made far too often, just as it was at the NFL Scouting Combine on Thursday, when a reporter asked Panthers coach Ron Rivera if he could draw a parallel between this year’s Heisman Trophy winner (Robert Griffin III) and last year’s winner (Cam Newton).

Panthers general manager Marty Hurney said Thursday he expects Jeremy Shockey to return in 2012. Earlier in the day, coach Ron Rivera said it was possible Shockey could retire.

Ron Rivera’s Carolina Panthers need to improve their run defense through this year’s draft.

Cam Newton promised to be an icon and an entertainer before he was even officially the No. 1 pick in the 2012 NFL Draft. Then, he went out and delivered with one of the greatest rookie seasons in NFL history. But he was still largely overshadowed.

Robert Griffin III made the rounds at Radio Row on Friday, when he bumped into another Heisman Trophy winner.

For a team that’s gone a combined 8-24 in the past two seasons, the Carolina Panthers sure are a confident bunch. Of course, that’s what happens when a player like Cam Newton bursts onto the scene.

Cam Newton and his teammates were having a little fun at the NFC’s Thursday practice, first sending out the rookie QB to return an Andy Lee punt, then lining the Panthers wide to catch a deep pass from Aaron Rodgers.

The Panthers are well represented in Honolulu. Cam Newton, Steve Smith and Ryan Kalil are here, and Smith decided to fly out his fellow wide receivers as well.

With featured fantasy running backs in short supply, Jason Smith runs down some of the league’s RB committees to determine who the best options are going forward.

As we will highlight in our “Tale of the Tape” this week — the Giants versus the Bills — we take particular interest in if and how a defense can get to the quarterback.