Retiring Yale President A. Bartlett Giamatti, a baseball outsider whose only connection with the game was rooting for the Boston Red Sox, yesterday was named 12th president of the National League.

Giamatti, who will become the third man to lead the league in the last 35 years, succeeds Chub Feeney. Feeney, 64, announced last year he would step down Dec. 31 after 17 years in office.

"I have been a lover of baseball for as long as I can remember," said Giamatti, 48, who was a literature professor before he become Yale president in 1978. "I have always found it the most satisfying and fulfilling game outside of literature."

Giamatti has no previous involvement with organized professional sports, but the Boston native has been a lifelong fan of the Red Sox. He has written sports stories and once said he would like nothing better than to become a league president.

The league owners unanimously approved Giamatti's appointment at a private meeting Monday. He signed a five-year contract for an undisclosed sum.

BASKETBALL

Nancy Lieberman, former star of two defunct women's professional basketball leagues, became the first female known to play in a men's professional league, appearing for three minutes in a U.S. Basketball League game in Springfield, Mass.

Lieberman, 27, a 5-foot-10 guard for the Springfield Fame, recorded the historic feat with 3:40 to play in the second quarter of a game against the Staten Island Stallions.

"I'm glad it's over," said Lieberman, who did not attempt any shots and did not score. ". . . It was in my mind that it was history and I think it finally got to me." . . .

About 250,000 fans, many wearing green Boston Celtics caps, shirts and buttons, crammed into Boston's City Hall Plaza to salute the champions of the National Basketball Association.

The Celtics beat the Houston Rockets, 114-97, Sunday to win the championship series, 4-2, and take the league championship a 16th time.

HOCKEY

Wayne Gretzky of the Edmonton Oilers, who broke his own records for assists and points last season, has been named winner of the Hart Memorial Trophy as the National Hockey League's most valuable player an unprecedented seventh time.

Rangers goalie John Vanbiesbrouck won the Vezina Trophy as the best goaltender, the first time a Ranger has won the Vezina since Eddie Giacomin and Gilles Villemeure shared it for New York in 1971.

Other winners: Troy Murray of the Chicago Blackhawks, Frank J. Selke Trophy as best defensive forward; defenseman Gary Suter of the Calgary Flames, Calder Memorial Trophy as best rookie; defenseman Paul Coffey of the Oilers, James Norris Memorial Trophy as top defenseman; Mike Bossy of the New York Islanders, Lady Byng Memorial Trophy for ability combined with sportsmanship.

Glen Sather of the Oilers was selected Coach of the Year in a vote by members of the NHL Broadcasters' Association. . . .

In other NHL news, the National Hockey League Players Association reached agreement with executive director Alan Eagleson on a five-year contract. . . . The league announced that the Soviet national team will oppose the NHL's all-stars in a pair of games next February. The two-game series in Quebec City between the Soviets and the NHL all-stars will replace the NHL's Wales versus Campbell conference format of previous years.

COLLEGES

Former Tulane University basketball star John (Hot Rod) Williams said he got $400 after one game that was allegedly fixed and $1,500 after another, but didn't know where the money came from and didn't shave any points to earn it.

The details were revealed Tuesday in a videotaped statement that Williams gave to the district attorney's office on March 26, 1985, the night he was arrested on sports bribery charges. The tape, played publicly for the first time in Williams' trial in state court, ran for about 20 minutes.

Williams is on trial on charges he helped shave points against Southern Mississippi on Feb. 2, 1985 and Memphis State on Feb. 20. His first trial ended in a mistrial last August.

TENNIS

Top seed Jimmy Connors, returning after a 10-week suspension, defeated Michiel Schapers, of the Netherlands, 6-1, 6-1, in the first round of the $237,400 Queens Club's grass court tournament in London.

Connors was banned for 10 weeks and fined $25,000 for walking off the court during a match with Ivan Lendl in Florida in February.

Defending champion Boris Becker, routed Ken Flach, of the United States, 6-2, 6-2.

BASEBALL

Ken (Hawk) Harrelson, continuing his reshuffling of the Chicago White Sox front office, has named former major league catcher Tom Haller to the job of general manager.

Haller, 48, had been managing the White Sox' Class AA affiliate in Birmingham. He previously was executive vice president of the San Francisco Giants.

Haller said he and Harrelson, who is vice president in charge of baseball operations, will be working together.

Harrelson, who last Thursday fired his chief assistant, Dave Dombrowski, because of a difference in "baseball philosophy," said, "Tommy is a solid baseball man. We will work together. I was becoming desk-locked."

GOLF

The U.S. Open field underwent its first alteration with the withdrawal of Tony Sills, a four-year touring pro from Los Angeles. Sills was forced to withdraw from the tournament in Southampton, N.Y., because of illness in his family. He was replaced in the field by Jim Albus.

OLYMPICS

Conflicting signs of progress appeared after the first day of talks in Lausanne, Switzerland, in the latest effort to resolve the dispute between North Korea and South Korea over where events of the 1988 Games will take place.

When asked how the day-long series of separate talks between International Olympic Committee officials and delegations from the two sides had gone, Chung Guk Chin, vice president of the North Korean Olympic Committee, said: "No progress."

Another member of the delegation, asked the same question, spread his thumb and index finger wide apart, then brought them slightly closer together.