Colon, who didn't miss a game the previous three seasons, likely will have season-ending surgery Wednesday. He injured the Achilles' tendon during a Monday workout and left the Steelers' facility on crutches.
Colon's injury is the latest blow to a Pittsburgh offense that will be without franchise quarterback Ben Roethlisberger for at least the first four games of the 2010 season because of suspension. Top wide receiver Santonio Holmes, facing a suspension himself, was traded to the New York Jets in exchange for a fifth-round draft pick this offseason.
The Associated Press contributed to this report.