D.C. City Council Chairman Sterling Tucker told baseball club owners at an informal gathering before the All-Star Game in New York Tuesday that his office is doing a marketing study to show Washington's fitness for another major league club.

Tucker, who was a personal guest of baseball commissioner Bowie Kuhn at a pregame dinner and at the game, said he expects the study will be completed in three or four weeks in time to present it to the owners at their annual summer meeting next month.

The study, being conducted by his aide, Alan Grip, will cover such areas as population trends, economics, employment, the use of the subway and the support of various college and professional sports here. The findings will be compared with other cities.

Tucker, who made a pitch for Washington baseball before 25 club executives in March, said yesterday he went to New York because "we have to use every opportunity to tell them our interest is very much alive for getting a baseball team."

Oakland A's owner Charles O. Finley boycotted the March meeting to protest a widely supported plan to have his American League club switch to the National League under new ownership. That plan was still the most popular one discussed during the All-Star festivities.

"We want to maintain contact with the owners because it helps us know what might be on their minds," Tucker said. "One owner asked me if the subway opened on time and were people using it. I was happy to tell them yes."

Tucker said he also reassured another owner that the leadership in the suburban communities, which help comprise a metropolitan population of about three million persons, are still supporting the return of baseball to RFK Stadium.

Tucker added he was pleased to see some congreeman at the game to reemphasize congressional interest in baseball's return after a six-year hiatus, Rep. Frank Horton (R-N.Y.) represented an ad hoc group of congressmen who have been trying to get baseball back here.

The club repeatedly mentioned as a solution for Washington's baseball void was Oakland, Tucker said. Club officials feel a shift to Washington would ease the stifling competition in the San Francisco Bay area where the NL Giants and AL A's are crippling each other at the box office.

A shift of leagues for Oakland - required because of territorial rights of the AL Baltimore Orioles - would create two 13-club leagues with some limited interleague play, a prospect some NL clubs dislike.

Potentials ownership for a Washington club 'wasn't a major consideration" of the owners he talked to. Tucker said. He added that some members of a group formed by the late Edward N. Cole, the former president of General Motors who died in a plane crash in May, are still interested in purchasing a club.

On other matter related to baseball, Tucker said he is anticipating the federal government will agree to pay half of the payment of the $19.8 million in bonds sold to build RFK Stadium when they fall due in December, 1979.

The U.S. government backed the bonds and is responsible for their redemption, plus whatever interest the city has paid on them. The future title of the stadium is still an open issue and Tucker hopes the city may get permanent control by sharing the bond payment.

"We'll probably reach an agrrement in the next few months . . . that there be some kind of sharing in the payments in the bonds," Tucker said, refering to the President's task force on the District of Columbia.

The group consists of the House and Senate District committees, the appropriations committees, White House representatives, the mayor and Tucker.

"The question has been raised about . . . what we are doing as a city to get baseball there (at RFK) and have maximum use of those resources," he said. "I'm sure if we got a team, that would help us in that issue (of getting federal money)"

Tony Coelho, a spokesman for Rep. B. F. Sisk (D-Calif), who heads the ad hoc baseball committee and is on the House Appropriations Committee, said federal assistance has been discussed for sometime.

"If there is attendance at the stadium, it may help the prospect of getting the stadium bonds payed off. You've got to have attendance there to justify (federal aid)," Coehlo said. Such aid, he added, would help remove a financial burden on the city and allow officials to work more aggressively for tenants.