3. James Harrison, 2008
This might be the best single-season by a Pittsburgh Steelers I recall witnessing in my lifetime. After playing sparingly in his first four seasons with the team, James Harrison exploded onto the scene in 2007 with a Pro Bowl year. In 2008, we all witnessed an exceptionally rare defensive performance.
At the age of 30 in 2008, Harrison recorded 101 tackles, 16.0 sacks, an interception, and led the league with 7 interceptions -- running away from DeMarcus Ware and his 20.0 sacks to earn Defensive Player of the Year honors.
Despite his squatty frame and pedestrian athletic traits, Harrison just made one play after another, and opposing offenses couldn't find a way to remove his impact from the game. Not only did Harrison finish as the DPOY in a year in which Troy Polamalu was also spectacular, but the outside linebacker finished fourth in MVP voting as well.
We all know how the story goes after this. Harrison would have an excellent stint in the playoffs followed by the famous interception-return touchdown against the Arizona Cardinals in Super Bowl XLIII. This season is simply one of the best you will ever see by a Steelers defensive player.