Hal Keller could have a gruff exterior, but those who got to know him — including the young Mariners players he guided — learned quickly he was a warm, caring person.

Keller, an executive with the ballclub for seven seasons, died in his sleep early Tuesday at his home in Sequim. Keller was 85.

Keller, who served as Seattle's general manager in 1984 and '85, had been suffering from esophageal cancer. He also endured a lengthy battle with diabetes that resulted in the amputation of a foot.

Keller played in the major leagues for the Washington Senators, appearing in 25 games as a catcher from 1949-52. He was the younger brother of Charlie "King Kong" Keller, a five-time All-Star with the Yankees.

Hal Keller made his mark as an executive, serving as the first farm director of the expansion Washington Senators, remaining with the organization through its move to Texas. He left the Rangers in 1979, coaxed away by Mariners president Dan O'Brien, his former boss in Texas.

"I learned so much from Hal," said Mariners president Chuck Armstrong, who joined the organization in 1983. "For me, he was the essence of a true baseball man. He loved and respected the game."

As the Mariners' director of player development for four years before becoming GM, Keller oversaw the drafting and development of players like Alvin Davis, Mark Langston, Harold Reynolds, Phil Bradley, Spike Owen and Darnell Coles.

"Hal was kind of a father figure to us, and by 'us' I mean the young guys in the minor-league system at the time he was director," Alvin Davis said Tuesday. "Sometimes, you were interacting about contracts and money, but other times you were interacting about ball and about life in general. During that time, I learned that Hal was a very caring person. It was more than a job to him, and the players were more than just assets."

By phone from Huntsville, Ala., where he manages the Class AA Stars, Coles called Keller "the most influential person I've known in baseball. It was just a wonderful time with the Mariners, and a lot had to do with Hal and the way he went about his business."

Coles, who had a 14-year major-league career, said Keller taught him the right way to play.

"Coming out of high school, I'd do some things like not running out a fly or ground ball," he recalled. "Hal would be the first one to let me know that's not how we do things here. He instilled in me that I have to carry myself like a professional."

Ken Phelps, another former Mariners player of that era, said of Keller in an e-mail, "Hal was easy to deal with. A gentle giant who played the game and cared about his players. Because he was a player, I believe that helped him become very good at evaluating talent. He was 'old school,' and there aren't many left like him in the game today."

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. He received the George Genovese Lifetime Achievement Award in scouting from the Professional Baseball Scouts Foundation in 2010. Keller was also a world-class bridge player, and a pioneer in the use of radar guns in scouting.

Larry Stone: 206-464-3146 or lstone@seattletimes.com.

On Twitter @StoneLarry