New York had until 4 p.m. Monday to activate or release Robinson, who returned to the team last week on a roster exemption following a four-game suspension for violating the NFLs substance abuse policy.
Robinson was arrested and charged with drug possession and carelessly driving in Morris County, New Jersey, last December. Police accused Robinson of having marijuana-laced candy in his car.
The Jets acquired Robinson from the 49ers last October for a fifth-round draft pick.
Wilcox signed with New York in June and had a solid training camp and preseason. But he had just three tackles in five games while never finding a consistent role in the defense.