James Harrison has been the leader of the Pittsburgh Steelers' defensive unit for quite some time. He has finally reached the last year of his deal and, while it was speculated that the 37-year-old would retire, it appears he intends to play out the rest of his contract and then retire with the black and gold.

The talented outside linebacker has been with the franchise every year of his career except when he jumped ship and joined the Cincinnati Bengals for the 2013 season. Harrison might be bigger than life right now, but he came from humble beginnings as he went to the Steelers as an undrafted free agent who had to prove his worth to the ball club.

Harrison has been one of the most dominant and productive Steelers defensive players in several years and could be one of the most imposing of all-time. During the 2015 NFL season, the 36-year-old recorded one start, but managed to rack up 40 combined tackles, five sacks, four pass defenses, an interception and two forced fumbles.

Throughout his career, Harrison has amassed a staggering 732 combined tackles, 76.5 sacks, 23 pass defenses, seven interceptions and 31 forced fumbles. The Steelers have lost a lot of depth players in free agency that have helped hide this roster's weaknesses for some time now and, with such a large exodus of talent, it will be curious to see how exactly the Steelers respond.

Pittsburgh lost left tackle Kelvin Beachum to the Jacksonville Jaguars, running back Jordan Todman to the Indianapolis Colts and full back Will Johnson to the New York Giants. Those were the losses on only one side of the ball - within the defense, they have lost defensive tackle Steve McLendon to the New York Jets, inside linebacker Sean Spence to the Tennessee Titans, cornerback Antwon Blake also to the Titans, cornerback Brandon Boykin to the Carolina Panthers and inside linebacker Terence Garvin to the Washington Redskins.

The Steelers may have lost a solid amount of players, however, they acquired several key playmakers, primarily tight end Ladarius Green who should come in and replace the retired Heath Miller. The Steelers also signed inside left tackle Ryan Harris, inside linebacker Steven Johnson and defensive tackle Ricardo Mathews to help give some depth to this defensive unit. With only $2 million in cap space left, Pittsburgh must wait until the draft to add any more quality players to the roster. Harrison should continue to be a source of solid, reliable production for the Steelers as they look to dominate their division once again.