Merlin Olsen, a Pro Football Hall of Fame defensive lineman who was part of the Los Angeles Rams' famed "Fearsome Foursome" of the 1960s, has died after a lengthy battle with cancer. He was 69.

Olsen, who was diagnosed with mesothelioma last year and had been undergoing chemotherapy, died Wednesday night, Utah State assistant athletic media relations director Zach Fisher said.

A Utah native, Olsen attended Utah State and, in his senior year with the Aggies, won the Outland Trophy as the nation's top interior defensive lineman.

Olsen was selected to 14 Pro Bowls and was inducted into the Pro Football Hall of Fame in 1982. A first-round draft pick of the Rams in 1962, he remains the franchise's all-time leader in career tackles with 915.

Following his retirement from the game, Olsen flourished as a television actor, appearing regularly on "Little House on the Prairie" in the 1970s before starring in his own series, "Father Murphy," from 1981 to 1983.

Olsen was part of the Rams' defensive line famously known as the "Fearsome Foursome" along with Roosevelt Grier, Deacon Jones and Lamar Lundy. Jones also is a member of the Hall of Fame. The line set an NFL record during a 14-game season in 1968 for the fewest yards allowed.