Harrison (knee) has been ruled out for Sunday's game, Chris Adamski of the Tribuen Review reports.
Harrison didn't practice all week, so this news doesn't come as much of a surprise. The 37-year-old will miss his first game of the season, but with the Steelers slated for a bye next week, Harrison will have plenty of time to recuperate for the next matchup against the Seahawks in Week 12.