Former New Orleans Saints linebacker Keith Mitchell has died at the age of 51, leaving the football world mourning the loss of a onetime Pro Bowl standout.

Texas A&M athletics announced Mitchell’s death Thursday. His cause of death has not been revealed.

Mitchell entered the NFL as an undrafted free agent after signing with the Saints in 1997. He quickly proved he belonged, spending five seasons in New Orleans and becoming one of the team’s most dependable defenders.

His biggest professional achievement came in 2000, when he earned a spot in the Pro Bowl.

Mitchell later played for the Houston Texans in 2002 before joining the Jacksonville Jaguars in 2003. He retired after seven NFL seasons.

Over the course of 94 career games, Mitchell recorded 408 tackles and 19.5 sacks.

Long before reaching the NFL, Mitchell was a dominant force at Texas A&M.

He played four seasons for the Aggies, earning All-Southwest Conference honors in 1995 and an All-Big 12 selection in 1996.

Mitchell finished his college career with an impressive 34 sacks, including 14.5 during a standout senior season.

His achievements earned him a place in the Texas A&M Athletics Hall of Fame in 2015.

News of Mitchell’s death stunned fans who remembered him as a hard-hitting linebacker and one of the Saints’ brightest defensive stars at the turn of the century.