Billy Birgfeld is a man who likes to think ahead. These days he's thinking of what a million people, give or take, might like to eat between innings at RFK Stadium in the summer of 1987.

"I figure about 400,000 hot dogs," said Birgfeld, president of B&B Caterers, the firm that handles concessions at the stadium. Add another 60,000 pounds of french fries and, say, 1 million cups of cola, and voila: lunch for a baseball season's worth of fans at home games.

Granted, those are just ballpark figures. But if the District succeeds in its push to land a major league baseball franchise, it could be a windfall not just for Birgfeld, but also for the local economy in general.

Officials here and in other cities that have lured expansion teams in the past decade say that a ball club typically injects $30 million to $80 million into the local economy annually and generates more than 500 jobs.

"Baseball is a boost to any city and a drain to the owner's resources," said Minor Lyle, a spokesman for the Chamber of Commerce in Seattle, home of the expansion Mariners since 1977. Twenty-one of the 26 major league teams, including the Mariners, reported that they lost money last year.

The average loss was $3 million and Jack Kent Cooke, who wants to bring a team to Washington, isn't talking of profits. "I would hope that a team in Washington would break even financially," he has said.

"Listen, it's been well worth it," said Toronto Mayor Art Eggleton. "It's been one of the best decisions we're made, a great boost to the city of Toronto. It's all you hear about in City Hall these days." The Toronto Blue Jays currently occupy first place in the American League East.

The D.C. Baseball Commission has urged local fans to open special bank accounts that reserve season tickets for a Washington baseball 1987 season. So far, 4,421 of the 81-game season tickets have been "sold." There has been a series of promotions during the past week designed to drum up more support for a team here.

The commission's goal is 10,000 season tickets by the end of July, in time for the August meeting of the baseball owners, who are expected to discuss expansion.

The economic impact of a team here would be felt primarily in the District itself, city officials say. But suburban politicians and chambers of commerce also are rooting hard for a home team, which they say could help to persuade businesses to settle in the Maryland and Virgina suburbs.

"To us it's primarily a life-style benefit, said Fairfax County Board Chairman John F. Herrity, a member of the D.C. Commission on Baseball. "That's not to be underestimated. Many corporations come here for the quality of life, and a ball team would be another nice amenity."

As an enticement for those corporations, the city baseball commission wants to build 52 luxury boxes as part of an overall renovation of RFK Stadium, which was erected in 1961. Firms seeking perquisites for employes and entertainment for customers could put down a handsome sum, which is not yet determined, for one of the boxes.

District officials say the type of jobs that would be created by a baseball team -- ushers, ticket takers and ticket sellers, grounds crews, clubhouse attendants and scoreboard operators, for example -- would be open to persons with relatively little education and skill.

"We've generated an awful lot of high-tech employment in downtown Washington, but there's still high unemployment," said D.C. councilman Frank Smith, chairman of the baseball commission.

"Baseball is the type of thing that could address the disequilibrium between the jobs generated and the skills that are out here."

Many of the jobs at RFK Stadium are now filled on a part-time basis for Redskins home games. Vendors and hawkers who work Redskins games say they make $75 to $100 a game, working on commission. Other employes are paid hourly rates by the Armory Board, which operates RFK.

"I'd really cash in if baseball came here," said Amos I. Custis, a part-time parking lot cashier at the stadium who worked for the old Washington Senators until they left town in 1971.

Custis, 66, a retired postal employe, said he could make an extra $1,500 a year working 81 home games for a local baseball team. "It would be a delight," he said.

One question mark in assessing baseball's potential impact on the local economy is game attendance.

Baseball commission members say -- maybe optimistically -- that 1.5 million fans would show up in a year to see a Washington expansion team play. At $7 a ticket, that's roughly $10 million in revenue at the gates.

Smith, chairman of the commission, said that means a total contribution to the economy of about $40 million a year. Some specialists say that figure would be greater, taking into account what economists call the "multiplier effect" -- the number of times a dollar ricochets around in the marketplace.

A local team also is seen as a boon to restaurants and bars, where televisions would be tuned into home games, and to hotels, where visiting teams, game officials and journalists would stay.

"It would be a big draw for my places," said Richard Danker, who owns a restaurant in Northwest and a sports bar in Southwest. Through his businesses, Danker sells package deals for Oriole fans, including game tickets and buses to Baltimore's Memorial Stadium and back for about 10 games a year. He figures that he could get more business with a team in the District.

Washington's gain, of course, would be Baltimore's loss. Oriole officials estimate that 20 to 25 percent of their fans come from the Washington area.

District officials figure that a team could be a shot in the arm for Metro.

About 60 percent of the 477,000 fans who attended Redskins home games last season traveled to RFK by Metrorail, and the city baseball commission is hoping that a baseball team would draw three times that number.

"It could only mean more revenue," said Metro spokeswoman Beverly Silverberg. "We'd welcome the extra ridership.