All four could fill positions of need, as San Diego's free agents include D-linemen Jacques Cesaire and Travis Johnson; linebackers Kevin Burnett, Stephen Cooper, Brandon Siler and Antwan Barnes; safeties Paul Oliver, Tyrone Carter and Pat Watkins; and center Scott Mruczkowski.
Austin (6-foot-3, 305 pounds) is a massive run stopper with the quickness to make plays in the backfield. He was suspended for his senior season after an investigation into whether some Tarheels players received benefits from agents, but he is still talented enough to merit a high draft pick.
The Chargers saw plenty of tape on Austin's 2009 campaign, though, as it was after that season that San Diego drafted UNC nose tackle Cam Thomas.
LB Dontay Moch
Keo (5-foot-11, 223 pounds) is a safety who can make plays in the box, as evidenced by his career numbers of 30 tackles for loss and 14 sacks. He also doubles as a punt returner, a handy skill with Darren Sproles set to depart as a free agent.
Linnenkohl (6-foot-2, 303 pounds) started the final 26 games of his career after taking over for Kyle DeVan, who now starts for the Indianapolis Colts. The Chargers always keep close tabs on Oregon State, having drafted from that school (CB Brandon Hughes) as recently as 2009.
Which positions should San Diego target in the draft? Talk in the message boards.
Michael Lombardo is a member of the Pro Football Writers of America and also a long-time contributor to the Scout.com network. His analysis has been published by the NFL Network, Fox Sports and MySpace Sports. You can see more of his updates by following him on Twitter.