As they say in sports, Paul Rotter just didn't have his good stuff last week when he took the mound for the Bristol Dodgers in a game against the Mets in Baldwin Harbor, N.Y. In six innings of work, he gave up all nine runs scored by the other team. What's more, he made the egregious mistake of issuing a walk to opposing pitcher Mickey Werner. When the final out was recorded, the Dodgers had scored only six times, and Rotter was charged with the loss. Not the sort of outcome he'd hoped for when he spoke with reporters before the game. Werner, he noted, had outpitched him before, so "I'm going to go out there and try to beat him." Ah, well, it's not as though either team was headed for the World Series. Indeed, what they were playing wasn't even baseball; it was softball. And the fact that Rotter lasted six innings was something of a feat in itself. You see, he and Werner play in a five-team league for senior citizens on Long Island. In their case, very senior. Rotter, a retired special education teacher, will be 87 on his next birthday. Werner, also a former teacher, is 93. He didn't last as long as his mound opponent, but then he allowed only one run before giving way to a relief pitcher. Both men throw left-handed and neither plans to hang up his glove anytime soon. "Why should I?" Rotter told the reporters. "Not only do I have fun; it's good for me." League officials say a record 106 players are participating this season.