Richardson, a third-year pro, started all 16 games for Kansas City last season after the team made him a sixth-round pick in 2008. The Clemson graduate has appeared in 32 games with the Chiefs, starting 17.
Gilberry started two games for the team last season and appeared in all 16 games as a role player along the Chiefs' defensive line. The 6-foot-2, 268-pound Gilberry signed with Kansas City an undrafted free agent out of Alabama in 2008.
The Star reports that running backs Jackie Battle and Tim Castille and offensive lineman Ryan O'Callaghan were not tendered by the Chiefs, according to their agents, making them unrestricted free agents.