Two-time Penn State football All-American Paul Posluszny retired from the NFL on Tuesday morning after 11 NFL seasons with the Buffalo Bills and Jacksonville Jaguars.

11 year veteran, former Pro Bowl MLB and 5 time Jaguars defensive captain Paul Posluszny today announced his retirement from the @NFL in the following letter https://t.co/5zopkqK1iC

— Jacksonville Jaguars (@Jaguars) March 13, 2018

He announced his retirement via a heartfelt letter released by the Jacksonville Jaguars. The linebacker spent seven seasons in Jacksonville, making his first and only postseason appearance in his final NFL season. He played in 145 games in his NFL career, making more than 1,200 tackles, recording 16 sacks, and intercepting 15 passes.

“Today is a sad day for me,” Posluszny said in his letter. “With much sadness but no regrets, I realize that I am no longer able to adhere to the unwavering standard of excellence that professional football demands. I love the game of football so much, and I know there is only one acceptable way to play.”

One of the many greats to make up “Linebacker U,” Posluszny was a rock in the heart of Penn State’s defense during his four seasons as a Nittany Lion.

He played in 40 games from 2003 to 2006, winning a Big Ten championship as a junior in 2005. He won the Chuck Bednarik Award — given to the nation’s best defensive player — twice, becoming one of just a handful of players to do so in college football history. He was the first player to record three 100-tackle seasons in Penn State history and finished his college career with a then-record 372 tackles.