A five-time Pro Bowler and 2008 NFL defensive player of the year with 70 career sacks, Harrison signed to a one-year contract after Jones suffered a broken right wrist Sept. 21 at Carolina. Harrison retired Sept. 5, but the club needed someone to step in who knew the defense.
''Right now, Jarvis is trying to be a student of the game, because he's hurt, and he's working hard to try to get back to being healthy,'' Harrison said Friday. ''But he's always asking questions, why I'm doing something one way or another, and he's taking notes to try to get as much information as possible.''
Jones, the Steelers No. 1 pick last year, started eight of 14 games during an uneven rookie season. After an intense offseason program, Jones appeared ready this year to secure the right outside linebacker spot Harrison vacated when he signed a free-agent contract with Cincinnati in 2013. However, any progress Jones made was stunted when he was injured in Week 3.
Jones had the cast removed Monday and has begun the rehabilitation process. There are still medical hurdles to clear, but Jones is on his way. He can begin practicing as early as the Steelers bye week, which begins after a Nov. 17 game at Tennessee, and then the club has three weeks to either activate him or put him on injured reserve for the rest of the season.
''I'm mostly just doing some things to improve range of motion,'' Jones said. ''It was pretty stiff when I first got the cast off, but it's slowly improving. I really can't do anything to try to strengthen it, because I'm just four days out of my cast. Maybe I can do that next week, so I just hope to continue to get better.''
If Jones can quickly get into shape and pick up near where he left off, the Steelers would be loaded at the linebacker position. Either Harrison or Arthur Moats, who has started the six games on the right side since Jones was injured, will have their playing time cut. While Moats has been solid, Harrison has made a bigger impact with four sacks in the past two games.
''I'll be ready when my number is finally called, but as long as we're winning it doesn't matter who gets the most snaps,'' Jones said. ''If it's me, I need to maintain the standard, getting sacks and making big plays.''
Until then, he'll continue to learn from Harrison and assistant coach Joey Porter, the Steelers starting right outside linebacker before Harrison.
''Those guys played this game very hard, and they were very productive,'' Jones said. ''If I even come close to what they accomplished, I'll have played a long time. So, I can't wait to get back on the field and get started.''
Notes: SS Troy Polamalu (knee) ILB Ryan Shazier (right knee), CB Ike Taylor (right forearm), S Shamarko Thomas (hamstring) and S Ross Ventrone (hamstring) are out this week. . The other only injured players are probable. WR Darrius Heyward-Bey (hamstring) and OLB Jason Worilds (abdomen) practiced on a full-time basis Friday.