Pittsburgh Steelers linebacker James Harrison and safety Troy Polamalu were both held out of practice on Thursday.

Harrison sat out the entire preseason and Pittsburgh's season-opening loss to the Denver Broncos with a left knee injury.

Polamalu missed practice with a calf issue, while tackle Max Starks (illness) and linebacker Stevenson Sylvester (knee) were also unable to practice.

Running back Rashard Mendenhall, who tore the anterior cruciate ligament in his right knee during Pittsburgh's final game of the 2011 season, fully participated in practice.