Dave Bresnahan opens the mailbox at his home in Tempe, Ariz., and occasionally finds a potato in it. Sometimes several potatoes. The potatoes have been sent to him by admirers, if you will, who request that he autograph and return them in the enclosed, self-addressed envelope.

Bresnahan, now a 35-year-old stockbroker with a wife and two small children, finds it curious that, after a decade, people should remember his unique contribution to baseball -- the day when, as a catcher in the minor leagues, he substituted a potato for a ball in a game.

''It's kind of weird, really,'' he said. ''I mean, when people hear that I was the Potato Guy that's all they want to talk about. About two years ago, Idaho had Potato Week and I was an invited special guest to Boise. But I was just part of the festivities. The highlight was the swimming pool, which was filled with 10,000 gallons of mashed potatoes.''

Bresnahan also has an invitation to return this summer to Williamsport, Pa., where, on Aug. 31, 1987, he executed his potato play. ''They're going to sort of honor me on the 10th anniversary of that game,'' he said.