PEORIA, Ariz. — When Jerry Dipoto pitched in the major leagues, as a reliever for three teams from 1993 to 2000, he was widely known among players for his vast memorabilia collection.

“Guys would talk about it: ‘This rivals the Hall of Fame,’ ” said Mike Hampton, the Seattle Mariners’ bullpen coach, who played with Dipoto in spring training one year. “They just said, ‘This place is unbelievable.’ He’s a baseball fanatic, a baseball nut. He loves the history of the game.”

Giants of baseball, like Frank Robinson and Buck O’Neil, would visit Dipoto’s home in Colorado to see his shrine, which included an autographed Christy Mathewson ball, a game-used Tom Seaver jersey and a handwritten letter from George S. Davis, a Hall of Famer who broke in with the 1890 Cleveland Spiders.

Alas, Dipoto has reduced his inventory during his itinerant career as an executive — the door signed by visitors was painted over in one of his moves — but he still spices his conversation with historical references; a Bill Mazeroski here, a Johnny Sain there. Last September, he began his third job as a general manager, with the Mariners, who own a distinction in the modern game: Seattle is the only current major league city that has never hosted the World Series.