Post-Gazette reporter Ed Bouchette reported (via. Jamison Hensely of ESPN) Steelers outside linebacker left the south side facility this afternoon without practicing, and a source told Bouchette his knee is "bothering him."
Harrison had arthroscopic surgery on his right knee Aug. 15, and has barely practiced since. He did do some work before Pittsburgh's Week 1 game at Denver, but was ruled inactive for that game as well as those in Weeks 2 and 3.
How much any of this means is suspect. The Steelers don't play this weekend, and it would seem strange they would trot Harrison out for a full workout before giving the players four days off for their bye week.
His absence, though, has been a big factor in the Steelers' 1-2 start. There's some improvement starting to show from Chris Carter and Jason Worilds, but with teams attacking the Steelers in the flats and short curls - right around where Harrison's physical presence is best utilized - quarterbacks should expect their game plans to include a heavy dose of their shorter throws.
It's worked well for both Broncos QB Peyton Manning and Raiders QB Carson Palmer, who have gone a combined 43-for-60 (71.6 percent) for 455 yards and five touchdowns. The Steelers are 0-2, facing both of these quarterbacks on the road and surrendering 65 points.