2011 Free Agency: Star rating is out of five. Age listing as of Sept. 1, 2011.
Ryan Kalil, C, Panthers. Age: 25. Franchised by Panthers
If the Panthers don't franchise Ryan Kalil, teams will be lining up to sign one of the top centers in the NFL.
Olin Kreutz, C, Bears. Age: 34. Signed with Saints (1 year)
It's not saying much, but Olin Kreutz was Chicago's best pass-protector in 2010. He's a declining player at this stage of his career, but he just doesn't miss any games; Kreutz made his 129th consecutive start in the season finale.
Lyle Sendlein, C, Cardinals. Age: 27. Re-signed with Cardinals
Arizona's best offensive lineman, Lyle Sendlein hasn't missed a start in three years. He needs to be re-signed.
Kyle Cook (RFA), C, Bengals. Age: 28.
Kyle Cook has been a solid, dependable starting center for the Bengals the past two years. He deserves an extension.
Jonathan Goodwin, C, Saints. Age: 32. Signed with 49ers (3 years, $10.9 million)
A serviceable starting center, Jonathan Goodwin still has a couple of quality seasons left in the tank.
Chris Spencer, C, Seahawks. Age: 29. Signed with Bears (2 years)
The injury-prone Chris Spencer had a rocky start to his 2010 campaign, but improved toward the end of the season.
Samson Satele, C, Raiders. Age: 26. Re-signed with Raiders
Samson Satele has done a decent job as Oakland's starting center the past two years after struggling in Miami.
Scott Mruczkowski, C, Chargers. Age: 29. Re-signed with Chargers
Scott Mruczkowski barely played this season, but filled in really well for an injured Nick Hardwick the year before.