Harrison, 39, has played 40 snaps through 14 games on the season and has just one sack.
Beyond that, Harrison should be another quality addition to the Patriots locker room as they eye a Super Bowl repeat. Harrison isn't a game-changer, but he can help. New England can seal the No. 1 seed in the AFC with a victory over the New York Jets on Sunday.
With his best days behind him, Harrison seemed destined to call it a career soon and settle into a long career as a TV personality on a pregame show somewhere. Chances are that if the Pats make it to the AFC title game, they're going to be staring back at Pittsburgh. He knows which guys are hurting and which guys have tells that the Patriots can use to their advantage.
The Patriots have made a habit of looking to veterans to fill out holes in their roster heading into the final weeks of the season.