On Tuesday, former Buffalo Bills linebacker AJ Klein, who played during two separate stints with the team, announced that he would be retiring from the NFL after 11 seasons. Klein put together a solid career after being drafted by the Carolina Panthers in the 2013 NFL Draft, and played for the Bills from 2020-2022, and again from later in 2022-the end of last season, after which he was not resigned.

Klein took to Instagram to announce the decision, noting that the occasion coincided with his 33rd birthday (via Alaina Getzenberg on X, formerly Twitter).

“Today is the first birthday I’ve celebrated not at a training camp in 15 years and it only seemed fitting to celebrate two milestones on this day. Today, I’m proud to announce that I’m officially retiring from the NFL after 11 seasons,” wrote the statement in part.

Klein also made sure to thank his teammates from over the years.

“Lastly, to my teammates, The Boys, who have been by my side through all the blood, sweat, and tears. The bonds we have formed, the camaraderie we have shared, and the memories we have created together will always hold a special place in my heart. I’m grateful for each and every one of you, It’s been an honor and a privilege,” wrote Klein.

Klein played his college football at Iowa State and was selected in the fifth round by the Panthers in 2013. His Bills tenure initially began in 2020 when he signed a three-year contract with the team that reunited him with former Panthers defensive coordinator Sean McDermott, who was (and still is) the head coach of the Bills.

One of his more memorable moments of that season came when he sacked Seattle Seahawks quarterback Russell Wilson twice in a late season game.

After being released by the Bills, Klein then had stints with the New York Giants, Baltimore Ravens, and Chicago Bears, before rejoining Buffalo in 2022, shuffling back and forth between the practice squad and main team for the next year and a half before deciding to call it a career this week.