Nat Frazier, former coach at Morgan State and more recently an assistant coach with the New York Knicks, will coach and be one of the financial backers of the new Washington expansion franchise in the Women's Professional Basketball League, it was learned yesterday.

Jerry Lewis, 40, who recently sold a dry cleaning and uniform business in Baltimore, will be general manager of the Metros. The league recently completed its first season with six teams and is expanding to 14 teams next season.

League teams will play a 36-game schedule and the Metros are negotiating to play their home games at the D.C. Armory. Sources said that perhaps one or two of 18 home dates will be played in Baltimore. The regular seasons runs from Nov. 15 to March 15.

"We have chatted with them and they have given us potential dates," said Robert Sigholtz, general manager of the D.C. Armory Board. "We are very excited about it. Our philosophy is, 'if you make a buck, we make a buck.' We don't want to chase anybody off."

Sigholtz said the Metros had requested 18 dates. Asked about the finances of the team, Sigholtz said, "it looks like it has substance."

Lewis and Frazier are minority investors in the team. Sources said the main backing comes from two "silent partners" in Maryland.

In New York, Bill Byrne, president of the league, said the corporation that was awarded the franchise lists Frazier as its president and Lewis as its only other officer.

"I can assure you they're financially strong," Byrne said. "They're backed by a corporation with $75 million in assets."

He said he was not at liberty to name the parent company.

Byrne also said he understood the schedule may be split, with nine games being played here and nine in Baltimore.

Sources said the Metros have given themselves three years and $400,000 to get going. The team reportedly needs to average 3,000 spectators per home game to break even and is looking to do so by the 1980-81 season.

Salaries in the league ranged last year from $5,000 to $15,000.

The Metro franchise cost $50,000. A franchise was awarded to Washington for the League's initial season but did not get off the ground and the team ended up playing in Dayton, Ohio. That franchise disbanded, the only one in the league to fold.

Although the Metros drafted 10 players at Tuesday's college draft, both Lewis and Frazier refused to comment yesterday beyond confirming that they are investors in the team and the roles they will play in its management.

Lewis said the Metros have tentatively scheduled a press conference Monday to announce their plans.

"We've been soft-pedaling it," Lewis said. "We've only been involved for 3 1/2 weeks. We had no players, no schedule, nothing set up. The corporation's structure has not been finalized yet."

Lewis said the team had hoped to hold its press conference before the league's draft, but was not able to.

"We didn't want to announce something and then have to change it," he said.

It was learned that, with trades, the Metros own the rights to 16 players.

Their No.1 draft choice Tuesday was 6-foot-4 center Willodean Harris of Alabama State, who averaged 16 points and 18 rebounds last season. She is described as "a strong player" by a person familiar with women's college basketball.

The Metros will play in the Eastern Division with New York, New Jerseay and the expansion team in Philadelphia. The Metros will play 16 games against division opponents and two games each, home and home, against the league's 10 other teams.

Iowas, Minnesota, Chicago, Milwaukee and St. Louis comprise the Midwest Division with California (based in Los Angeles), San Francisco, Dallas, Houston and New Orleans in the Western Division.

The league recently moved its offices from Columbus, Ohio, to New York City and Byrne said it is putting together a national television package for next season with Hughes Sports Network.

Byrne said the New York team, which played most of its games in high-school gymnasiums last season, will play 11 games in Madison Square Garden and seven games in the Garden's Felt Forum next season. The New Orleans expansion franchise will open in Superdome, he said.