Raiders Legend Daryle Lamonica Dead At 80

The NFL has lost a member of its family -- Raiders legend Daryle Lamonica died Thursday morning, officials confirmed to TMZ Sports.

He was 80 years old.

"The Raider Nation will forever miss his easy-going nature and warm smile," the Raiders said in a statement after his passing. "Our deepest condolences are with his wife Mary, son Brandon, the rest of the Lamonica family, teammates, and friends."

The Fresno County Sheriff-Coroner's Office tells us the former quarterback passed away at his Fresno home ... and the death "is considered to be one of natural causes."

Lamonica played 12 seasons in the NFL, spending four seasons with the Buffalo Bills and then eight with the Raiders, where he became a…