If Atlanta relief pitcher John Rocker carries out his threat to ride the subway to games between the Mets and the Braves, there could be more cops on the train than purple-haired punks, unwed mothers and AIDS patients combined.
Security at Shea Stadium will be tight. And Mets fans itching to taunt Rocker — who angered New Yorkers with his politically incorrect views on punks and foreigners riding New York subways — may find their anger dulled by a two-beer limit.
   Last week, Rocker told USA Today Baseball Weekly that he planned to ride the No. 7 subway train through Queens during the Braves-Mets series that starts Thursday.
  “I won’t be in a cab,” he vowed. “I won’t be on the bus. I’ll be on that train.”
Police said Tuesday that Rocker can take the subway, which passes through many immigrant communities. But he may have trouble starting a meaningful dialogue with other riders.
   “If Rocker gets on the train, he’ll be entirely surrounded by police officers,” police spokeswoman Marilyn Mode said.
   Once he gets to the stadium, he’ll be protected by a sea of blue. Mode said that in addition to the 60 officers usually assigned to Mets games, there will be an extra 500 uniformed cops plus an unspecified number of plainclothes officers.
   And that’s not all. Police sources who spoke on condition of anonymity told The Associated Press that officers will be on every subway platform along the No. 7 line between Grand Central Terminal in Manhattan and Shea in Queens, and any train Rocker boards will become an express so that it picks up fewer pa at the games to blend in.
   Meanwhile, Mets senior vice president David Howard said that fans would be allowed to buy only two beers at a time during the four-game series. The normal limit is four.                   Howard said beer sales will stop after the sixth inning instead of the usual seventh.
   “I’m confident New Yorkers will rise above the situation and not stoop down to his level,” Howard said.
Baseball commissioner Bud Selig, in town to unveil the new World Series championship trophy, said he had discussed security arrangements with Mayor Rudolph Giuliani, police officials and Rocker, and was satisfied that all precautions have been taken.
   “It’s time to be prudent and smart,” Selig said. “The Mets fans will be just fine and I don’t think John will do anything to incite anybody.”
Rocker became a target of fan ire here when he told Sports Illustrated during the offseason that he would rather retire than play for a New York team.
   “Imagine taking the 7 train ... looking like you’re (in) Beirut next to some kid with purple hair, next to some queer with AIDS, right next to some dude who got out of jail for the fourth time, right next to some 20-year-old mom with four kids,” he said. “It’s depressing.”
   He added: “The biggest thing I don’t like about New York are the foreigners. You can walk an entire block in Times Square and not hear anybody speaking English. ... How the hell did they get in this country?”
   The series this week will be the hurler’s first trip to Shea since the story appeared.
   Braves and Mets players had varying opinions on the controversy.
   “All I’m thinking about is going up there and doing my job on the mound,” said Braves starter Kevin Millwood, who is scheduled to pitch Friday. “I think major league baseball and security at Shea Stadium is smart enough to prevent having anything bad from happening.”
   Mets catcher Mike Piazza said: “I’m sure the crowd will be loud and rowdy. That’s what New York baseball is all about.”
   And if ugliness does break out on the subway, the Mets will come to the rescue — in a comic book. The team has commissioned a 24-page comic book featuring a villain who wants to blow up a No. 7 train. The bad guy and his robotic henchmen are defeated by the Mets’ multiracial lineup, with reliever John Franco pounding the villain, named Larcenous Vein, into outer space with his baseball bat. The comic book will be handed out to fans 14 and under at Saturday’s game.
   The team said no similarity between Vein and Rocker was intended.
   “It’s a coincidence,” said Mets spokesman Jay Horwitz. “The idea was conceived a long time ago.”