Cincinnati Reds pitcher Mario Soto pleaded innocent yesterday to simple battery charges for allegedly punching a waiter in an Atlanta nightclub.

Soto was arrested about 12:45 a.m. The alleged incident at the Limelight disco occurred shortly after he pitched Tuesday night's 2-1 victory over the Atlanta Braves. Waiter Jon Sarbucher said Soto struck him twice in the face after an argument. Soto, 28, was ordered to appear for trial June 14, the next time the Reds are in Atlanta.

Soto, an 18-game winner last season, was involved in a brawl with the Braves during a game in Atlanta last season after he hit outfielder Claudell Washington with a pitch. Soto received a five-day National League suspension for that, after drawing a five-game ban a couple of weeks earlier as the central figure in a brawl at Chicago . . .

The Major League Players Association, in a New York bargaining session, asked the baseball owners for more detailed financial data on each team and Lee MacPhail, president of the Player Relations Committee and management's chief negotiator, said he was pleased with the union's request.

"We will cooperate to the best of our ability and as promptly as we can," MacPhail said, adding that subcommittees for the two sides would meet today to work out the "mechanics and ground rules" of providing the requested data . . .

Although some of the 16 area banks that have agreed to accept deposits on tickets to Washington's as-yet-nonexistent baseball team were not ready to begin opening accounts yesterday, the matter should be cleared up today, according to a spokesman at D.C. National Bank.

Spokesmen at National Savings & Trust and First American said they had not received the proper paperwork to set up the accounts and announcement of the drive by the D.C. Commission on Baseball may have been "a little premature." "I found out about it from The Post," said one.

Marsha Gallagher, D.C. National marketing director, said the delay was brief and caused in part by enlistment of three other banks, in Maryland, in the drive to help land major league ball.