Troy Polamalu announced his retirement from the Pittsburgh Steelers and the NFL late Thursday night with an interview with steelcityinsider's Jim Wexell.

A not-so-surprising move brings with it mountains of emotion, as the most exciting player in franchise history walks away from the game after eight Pro Bowl, five All Pro selections, three AFC Championships, two Super Bowl title and a Defensive Player of the Year award.

The decision loomed over the offseason, as Polamalu, who was signed to a three-year extension last season, had a salary cap number of $8.25 million, and a $6 million salary for 2015.

The remaining prorated portion of his signing bonus accelerates to this year's cap, but the Steelers still save $3.75 million in cap dollars with $4.5 million in dead money.

Polamalu's statistics are impressive, but do not define the career of the one of the most extraordinary defensive players in franchise history. His trademark was leaping over the line of scrimmage just as the ball was snapped - a move duplicated by several players in recent years.

Perhaps his finest moment came in the Steelers' AFC Championship win over the Baltimore Ravens after the 2008 season. With under two minutes to play, the Steelers led 16-14 and Baltimore was trying to pull off a late-game comeback victory.

Polamalu followed then-rookie quarterback Joe Flacco's eyes, and jumped into a previously open passing lane. His interception sent the capacity crowd at Heinz Field into a frenzy as he returned the pick 40 yards for a touchdown with a sideline-to-sideline weave through the Ravens that sealed the win and created one of the most powerful highlights in team history.

His overruled interception in a divisional playoff game against the Indianapolis Colts is also a part of his legacy. Polamalu at his freakish best, followed the eyes of Colts QB Peyton Manning, and made a bounding interception. Upon getting up from the turf at the RCA Dome, Polamalu appeared to take a step, and in doing so, knocked the ball from his arm with his knee. He recovered it and laid on the ground, securing what would have been essentially a game-clinching interception.

The interception-then-fumble-recovery was overruled on the field, a decision the league would later declare to be incorrect. The Colts scored on the drive, and after Jerome Bettis' infamous goal-line fumble. the Steelers' defense forced a long field goal attempt. The kick was missed, and the Steelers advanced to the AFC Championship game. Two games later, the Steelers won the franchise's fifth Super Bowl in a 21-10 win over the Seattle Seahawks.

Polamalu and the Steelers would return to the Super Bowl three seasons later under head coach Mike Tomlin. Pittsburgh's top-ranked defense was anchored in part by Polamalu's athleticism and unpredictability.

He ascended to Defensive Player of the Year in 2010 after a seven-interception season for the league's best defense. He suffered a knee injury late in the regular season, and did not appear to be 100 percent in the playoffs, that ended with loss to Green Bay 31-26 in Super Bowl XLV.

Polamalu is active in local and national charity foundations, and is deeply but quietly religious. He is recognized throughout the NFL and beyond as a man of impeccable character.

Troy Polamalu isn't a football player in Pittsburgh. He's an institution, on the same level as "Mean" Joe Greene, Terry Bradshaw, Jack Lambert and Jerome Bettis.

There will never be another Troy Polamalu.

(Neal Coolong helped contribute to this story.)