Mark McGwire, the Oakland Athletics first baseman who broke the major league record for home runs hit by a rookie when he totaled a league-leading 49, was unanimously named the Jackie Robinson American League rookie of the year yesterday by the Baseball Writers Association of America.

McGwire finished the season with 11 more homers than any other first-year player in major league history. He became only the second AL player to unanimously win rookie honors. The other was Carlton Fisk of Boston in 1972.

In the voting by two writers from each AL city, McGwire received all 28 first-place votes for 140 points. Points were awarded on a 5-3-1 basis for votes from first through third.

The 24-year-old from Claremont, Calif., hit .289 and knocked in 118 runs in becoming the second straight Oakland player to win the AL rookie honor. Jose Canseco won in 1986.

Third baseman Kevin Seitzer of Kansas City was second in the balloting with 64 points and catcher Matt Nokes of Detroit was third with 32 . . .

Lance Parrish of the Phillies went one for four in a 9-3 loss to the Atlanta Braves on July 12, but earned an extra $200,000 for his day's work.

Andre Dawson of the Chicago Cubs went one for four in a 12-0 loss to the Los Angeles Dodgers that afternoon and made $150,000.

Steve Balboni of the Kansas City Royals went zero for four against the Oakland Athletics Sept. 20 and made $65,000.

All had incentive bonus clauses in their contracts that guaranteed them the extra money if they were not injured by certain points of the season.

A study of baseball salaries published in yesterday's editions of the New York Times and contract details obtained by the Associated Press reveal that several players earned more in bonuses than they did in salary.

According to the Times, there were 57 players who made more than $1 million and six of them made more than $2 million -- Dan Quisenberry, George Brett, Jim Rice, Eddie Murray, Mike Schmidt and Gary Carter.

The $200,000 Parrish received for being in that July 12 game was a bonus for not being on the disabled list at the time of the all-star break, and it made him a 1987 millionaire. His salary was $800,000.

Balboni was released by the Royals following the 1986 season. He earned $625,000 but hurt his back Sept. 9 and missed the remainder of the season.

Kansas City offered him a 1987 contract that guaranteed only $100,000, but included bonuses of $65,000 for every 30-game period in which he was not on the disabled list . . .

Dave Johnson says he would like to remain the New York Mets' manager past next season rather than move into the club's front office, Newsday reported. Johnson, whose contract expires next season, said he has changed his mind on moving upstairs and now wants to be among the list of managerial candidates for beyond 1988 . . .

A news conference will be held this morning at 9:15 in the Senate Radio/TV Gallery to announce formation of a Senate Task Force on Expansion of Major League Baseball.

Recently, 15 senators wrote to Baseball Commissioner Peter Ueberroth, American League President Robert Brown and National League President A. Bartlett Giamatti, inviting the three to meet with the task force to discuss expansion.