The 36-year-old Thomas was released Saturday along with 12 other players. The fifth-round pick by Miami in 1996 signed with the Chiefs as an unrestricted free agent after playing last season with Dallas.
The Chiefs were counting on his veteran presence to help smooth the transition to a 3-4 defense under first-year head coach Todd Haley. But Thomas was injured early in training camp and never returned. The Chiefs never specified his injury.
Other players cut included Bernard Pollard, who started the past two years at safety, and veteran wide receiver Ashley Lelie.
Guard Colin Brown was placed on injured reserve.