Texas A&M defensive end Justin Dunning has announced that he is retiring from football.

The redshirt sophomore cited lingering problems from knee injuries and surgeries in a post on Twitter Friday evening.

Dunning has undergone multiple knee surgeries since high school, according to a report from SportsDay in Dallas.

“I will always love and be a fan of the game of football, but past injuries that have left lingering pains have made it difficult for me to keep playing,” Dunning said. “I am grateful for every obstacle that I had to leap over on my road to recovery, but now I am at the end of that road and it is time for me to walk a different path.”

Dunning played in seven games this season and made seven tackles, including one sack. Throughout his career, he played in 18 games. He recorded 20 tackles as a freshman.

Last year, he suffered a season-ending knee injury during preseason practice. It was the third time in his career he had torn a knee ligament, the SportsDay report noted.

This season, Dunning was beginning to work his way into the rotation before hurting his knee again vs. Mississippi State on Nov. 18.

It has been an unfortunate career for Dunning, as he’s had to battle so many knee injuries.

Still, he seemed positive in his Twitter post on Friday.

He even noted he was writing the letter “with a smile on my face.”