Troy Polamalu is retiring after 12 seasons in the NFL. A surefire Hall-of-Famer, Polamalu will go down as one of the best safeties to ever play the game. He was an instrumental part of some great defenses that led the Steelers to two Super Bowl wins and three appearances. But what was it that made him so special as a player?

Polamalu’s quickness, speed and aggressiveness made him a great safety, but it was his instincts that separated him. Those instincts allowed defensive coordinator Dick LeBeau to turn Polamalu loose. LeBeau called defenses that gave Polamalu the option to freelance. His instincts, ability to read and react to the offense’s formations and plays, and his athleticism would take over at that point.

The way in which Polamalu roamed the field made him difficult to account for as an offense. In his prime, he could hang back deep, 15 yards from the line of scrimmage, and then sprint in at the snap unblocked to stop the running back for no gain. Why was he unblocked here? Because he was so deep at the snap that he wasn’t accounted for in the blocking scheme by the offensive line. Very few safeties have been capable of this style of play.

Other times, Polamalu would play in the box where he WAS accounted for in the run-blocking scheme, anticipate the snap count, sprint up to the line of scrimmage before the offense could adjust, and power through into the backfield untouched. His instincts, quickness, and aggressiveness allowed him to do things like this regularly in the running game.

Polamalu had a similar impact in the passing game. We’ve seen him start at the line of scrimmage, showing a blitz, and then sprint back at the snap to be the deep half safety in cover-2. We’ve rarely seen other safeties do this as effectively as he did. Polamalu would read and jump routes to make big plays as well, sometimes abandoning what his responsibility technically was on the blackboard. Most of the time, he ended up being right though.

Football is very much a game of strict responsibilities. Plays are called based on tendencies. Each player has an assignment. Those plays and assignments can be altered before and during the play based on the other team’s alignment, but when you can’t predict where players on the other team are going to be, it makes it that much more difficult to fulfill your assignment or have the right play called. This was what made Polamalu such a pain for offenses to deal with. They rarely knew where he would end up after the snap.

It was clear in the last year or two that Polamalu was not the same player physically. This hurt his ability to freelance as effectively as he did in his prime and play the same way. It’s understandable that he’s retiring now.

Without Troy Polamalu, though, the Steelers defense would not have been as good as it was over the last decade. They definitely wouldn’t have won two Super Bowls and made it to three. He’s a first-ballot Hall-of-Famer, and one of the best to ever play the game.