Chris Maragos, a safety and special teamer who spent four seasons with the Eagles, announced Tuesday that he was retiring from football due to a knee injury.

Maragos, 32, was a free agent. He last appeared in an NFL game in October 2017, when he tore his ACL and PCL during Week 6 of the Eagles’ Super Bowl season.

He spent the 2018 season on the physically unable to perform list before being released during the offseason.

In a post on Twitter, Maragos thanked his teammates, coaches, hometown and family for their support. He also had a special shoutout for Eagles fans.

“To all the fans that supported me, especially Eagles fans, thank you from the bottom of my heart,” he wrote. “I’ve tried to put on display every single snap how I think each and everyone of you would play the game if you were able to. I hope I’ve made you proud by the intensity and passion that I played with, by leaving it all on the field every single time I stepped between the lines.”

The Wisconsin native began his college career at Western Michigan as a receiver. He transferred to the University of Wisconsin and switched to defense. After going undrafted in 2010, Maragos signed with the 49ers and spent time on the practice squad while appearing in three regular-season games.

After being released ahead of the 2011 season, Maragos signed on to the Seahawks’ practice squad and parlayed it into 11 game appearances. He appeared in all 16 games in 2012 and signed a one-year deal to stay in Seattle ahead of the 2013 season. The Eagles signed him to a three-year contract in 2014 and an extension in 2016.

As an Eagle, Maragos excelled on special teams. He appeared in all but one regular-season game in his first three seasons in Philadelphia.

Maragos retires with two Super Bowl rings -- 2013 with the Seahawks and 2017 with the Eagles.