Hal Keller, a former Seattle Mariners general manager and longtime Texas Rangers executive, died in his sleep at his home in Sequim early Tuesday.  He was 84.

Keller, who served as the Mariners’ general manager in 1984 and 1985, had been suffering from esophageal cancer, The Peninsula Daily News reported.  He also endured a lengthy battle with diabetes that resulted in the amputation of a foot.

Keller spent most of his baseball career in scouting and the front office and was the first farm director of the expansion Washington Senators. After the Senators moved to Texas and became the Rangers, Keller introduced the radar gun, which measures the speed of pitches.

Keller left the Rangers in 1979 and became the Mariners’ director of player development, a post he held for four years before becoming the general manager.

Keller retired from the Mariners in 1985, returning briefly to baseball in 1989 as a scout for the Tigers. He also had a stint scouting for the Angels. Keller retired for good in 1999 and settled in Sequim with his wife, Carol.