ANAHEIM, CALIF., AUG. 12 -- The fringe player's worst enemy -- the numbers game -- today victimized Mickey Weston for the second time this season, as the Baltimore Orioles finally moved to compensate for their recent manpower shortage at first base.

Following this afternoon's 11-6 victory here over the California Angels, the Orioles optioned pitcher Weston to Class AAA Rochester and recalled Chris Hoiles from the Red Wings. That leaves the club with nine pitchers, but Manager Frank Robinson said he plans to use a four-man starting rotation for the next few weeks; two off days in the next two weeks will help.

Hoiles is needed at first base, with Randy Milligan unlikely to go on the disabled list but unavailable at least temporarily because of a bruised shoulder. In addition, Ron Kittle is hobbled by a pulled groin, Sam Horn has too many defensive limitations to be entrusted with the position regularly and Mickey Tettleton is no more than an emergency solution.

"It's another one of those situations where I can't argue with them," said Weston, who allowed nine earned runs in 7 1/3 innings during two starts since being added to the roster when Bob Milacki went on the DL two weeks ago. His fate may have been sealed even before his 3 1/3-inning, eight-hit, seven-run outing Saturday night that produced a 12-4 loss to the Angels.

"It's a legitimate thing," he said. Milligan "is hurt, Kit is hurt and they need somebody to play first base. . . . I was told it wasn't because of my performance as much as the need for another body."

Milligan said today his shoulder is improving but added he's still at least five days away from seeing game action. Kittle is available to play but is limited.

Weston's first demotion this year came when the Orioles cut their pitching staff from 11 to 10. The right-hander was 10-0 with a 1.81 ERA at Rochester between his two stints with the Orioles.

"Weston is the victim of our physical ailments," General Manager Roland Hemond said. "If we run into a {pitching shortage}, we can call someone up. In the meantime, we need position players."

Hoiles, who also can play catcher and third base, batted .364 in 66 games at Rochester since being demoted from Baltimore a month ago. He was four for 28 in a 10-game stint with the Orioles.

Hemond said Hoiles was called up instead of David Segui -- a better defensive first baseman -- because of Hoiles's versatility and because he'll provide a right-handed bat. Segui is a switch hitter whose hits better from the left side.

Hemond also said the move was unrelated to any possible transactions involving catcher Tettleton -- whom the club apparently would be willing to trade. Tettleton will be a free agent at the end of the season, and indications are the team has shopped him around to determine his market value.

Meanwhile, the four-man rotation likely would have come about even if Weston had stayed. Robinson's usual policy is to trim the rotation when he feels a crucial stretch is approaching; as the Orioles battled the Toronto Blue Jays until the final series last year, he often used pitchers on three or even two days' rest during the season's last six weeks.

The move will maximize the number of appearances for Ben McDonald, Dave Johnson, Pete Harnisch and today's starter, John Mitchell. When a fifth starter becomes necessary, it will be Milacki, who's on schedule to have his strained right shoulder healed sufficiently to pitch when he's eligible to come off the DL Aug. 21. . . .

McDonald, 4-0 this season and 5-0 in his brief career, can establish a team record Monday as he attempts to win his first six major league decisions. Already he has won his initial four big league starts, making him the first pitcher since Fernando Valenzuela of the Los Angeles Dodgers to accomplish that feat. Valenzuela captured his first eight starts in 1981, a span that included seven complete games and a 0.50 ERA.