The 34-year-old Cesar appeared in 58 matches over the past two seasons, though he only had three goals and three assists in MLS games. He was also in the starting lineup when Sporting KC won the U.S. Open Cup this year.
Hedrick fractured his left fibula in May, ending the 23-year-old rookie defender's season.
Markovic made two regular-season appearances for Sporting KC, and his release will open up an additional international slot on the roster.
Warzycha, a former third-round pick, made his MLS debut in a victory over Toronto FC on June 16 for his only league appearance. He also appeared in two U.S. Open Cup games.