In addition to Harrison, the Steelers also removed Jason Worilds , Harrison's backup, off the PUP. If all goes well, Harrison and Worilds each could play in the game, although it might be on a limited basis. Harrison, a former NFL defensive player of the year, and Worilds have not practiced since the spring and will not dress Thursday night for the preseason finale against the Carolina Panthers. Inside linebacker Stevenson Sylvester, who has been used outside in training camp because of the injuries to Harrison and Worilds, sprained the medial collateral ligament in his knee during the final practice at St. Vincent College. Post-activation, neither linebacker is eligible for the reserve/PUP list that would keep them out for at least six games while allowing the Steelers to fill their roster spots with other, healthier players. Since the spring, Harrison has tried twice to test his knee in agility drills, and each time the knee swelled after cutting on it. They activated running back Rashard Mendenhall and defensive tackle Casey Hampton amid uncertainty about when they would be fully prepared to get back on the field and it’s believed Mendenhall will be out for several weeks of the regular season.