WITH THIS NEW COMPUTER GAME YOUR SOFTBALL TEAM MIGHT BEAT THE YANKS

When the Roslyn (N.Y.) Savings Bank's softball team beat the New York Yankees 11-5, Rightfielder Bob Gardner fielded flawlessly and hit a double off Ron Guidry. Gardner had the kind of day they dream about in the Garden City Softball League because he's the guy who wrote the computer program.

A 28-year-old graduate of the Harvard Business School, now a systems consultant for The New York Times, Gardner has designed a new baseball game to play on IBM Personal Computers. He put the 1982 statistics of 650 players from all 26 major league teams onto a floppy disc. Then he scoured The Baseball Encyclopedia for stats of the players on 16 pennant-winning clubs dating back to the 1927 Yankees. For his own delectation, he couldn't resist sticking in the figures for the guys on his Long Island softball team, which had a collective batting average of .480 in 1982.

Gardner's program lets you pretend you're Tommy Lasorda, Ralph Houk or even Miller Huggins. You can pick the lineups, send in pinch hitters, change pitchers and call for steals and hit-and-run plays. Defense options range from drawing in the infield to guarding the foul lines to pitching around a batter. The software is sophisticated enough to account for home-field advantage and a particular pitcher's endurance.

On the display board, the game appears as a miniature diamond with the names of the pitcher and the batter. If the batter gets a hit, one hears the blip of the bat hitting the ball and the batter's name advances to first base. The action is accompanied by a kind of electronic Muzak that occasionally punctuates the game, starting with The Star-Spangled Banner (and, if either Toronto or Montreal is playing, O Canada). Take Me Out to the Ball Game comes on during the seventh-inning stretch, and a late home-team rally with two men on is accompanied by the inevitable "Charge!"

You can play against the computer, against another person or even plug in the lineups, set the game on automatic and read the printout box scores two minutes later as though the teams were playing out of town.

Gardner is selling the program (his bank's softball team is not included) through North Shore Software in Manhasset, N.Y. for $35. He doubts that it will make much of a dent in the mail-order baseball board game market. Richard Seitz, the mahatma of APBA, one of the best of those games, thinks that Gardner's electronic approach is like renovating an automat into a fast-food drive-in; the service is faster and it's sort of the same product, but the flavor is gone.

Gardner hopes to sell his programs to many of the half-million owners of IBM Personal Computers, but chances are George Steinbrenner will never be interested in one when he learns that Roslyn Savings Bank beat the Yankees.