OAKLAND, AUG. 7 -- The Baltimore Orioles began a crucial tour of the West tonight by toying with doom. In the same place and at approximately the same time their magical season of 1989 started a debilitating collapse, the Orioles watched their ever-expanding injury list grow by two and suffered a tough loss to the Oakland Athletics.

Baltimore's 3-2 defeat before 40,117 at the Oakland-Alameda County Coliseum was only the last of the day's heartaches. What hurt the Orioles most was first baseman Randy Milligan leaving the field with a shoulder injury in the first inning after barreling over A's catcher Ron Hassey, then catcher Mickey Tettleton exiting an inning after being struck on the elbow by a Bob Welch fastball.

Both injuries turned out to be bruises, and each is listed as day to day. The Orioles' loss, meanwhile, was no less disquieting for them. They squandered a two-run first-inning lead and wasted a mostly solid 6 2/3 innings by starter John Mitchell when Walt Weiss's single provided the tie-breaking run in the seventh.

Hassey began the winning rally with a single, moved to second on Felix Jose's sacrifice and scored on Weiss's sharp base hit to right field. That made a winner of Bob Welch, who outdueled Mitchell to pick up his major league-leading 18th victory. Rick Honeycutt and Dennis Eckersley finished, with Eckersley picking up his 36th save.

"It's tough on us," Baltimore Manager Frank Robinson said. "We lost a real tough ballgame, and we got some more people banged up. . . . We can't afford to lose our front-line people and still be competitive."

The Orioles dropped to 53-55 overall and 27-29 on the road. They had won 16 of their last 21 games against AL West opponents, but fell six games behind Boston in the AL East.

The A's improved to 69-41, remaining three games ahead in the West while beating the Orioles for the fifth time in seven meetings this year. The Orioles' day was so grim that the stadium lights went out for 18 minutes as they prepared to bat in the second. It was only natural that Ron Kittle's bid for a two-run home run off Honeycutt in the eighth fell into Doug Jennings's glove at the left field wall.

The Orioles jumped on Welch in the first inning, though they emerged with more lost than gained. Welch -- who has allowed the Orioles but three earned runs in 22 1/3 innings this year and five earned runs in 38 career innings here -- surrendered one-out singles to Joe Orsulak and Milligan, breaking his zero-for-16 rut against Oakland.

That brought up Sam Horn, who leaned into a belt-high fastball and laced it to left-center. Orsulak scored, and third-base coach Cal Ripken Sr. waved around Milligan as center fielder Dave Henderson's throw from the warning track headed for cutoff man Weiss.

Weiss's relay to Hassey and the 230-pound Milligan reached the plate at roughly the same time. With Hassey blocking the plate, Milligan lived up to his nickname "Moose" and separated the ball from the catcher by lowering his left shoulder and executing a block that would make any Hog envious.

The Orioles led, 2-0, but Milligan emerged woozy and in pain. He was immediately replaced by Kittle and taken to a nearby hospital to have the shoulder X-rayed; those X-rays proved negative. The infield is already depleted; second baseman Bill Ripken is on the disabled list with a stress fracture in his right foot and third baseman Craig Worthington has a sore hamstring.

Milligan has been in a recent drought -- 13 games without an RBI while his average dropped from .275 to .261. But he remains the club's leading power source with 20 home runs and 88 walks.

The uprising left the Orioles temporarily with a 24-1 first-inning scoring edge over their opponents in the past 15 games. But Mitchell (4-4), starting for the first time on three days' rest, gave away the advantage quickly amid a two-out Oakland rally in its half of the first.

Carney Lansford doubled into the left field corner with one out and, after Jose Canseco flied out, Henderson followed with a run-scoring double to almost the same spot. Mark McGwire produced then an RBI single to left to tie the game at 2.

The Orioles suffered the next blow in the sixth when Welch hit Tettleton just above the elbow with a pitch. The Orioles' catcher remained in the game until Bob Melvin came in in the middle of the seventh. The A's did not escape either: Rickey Henderson left after the fifth inning with a strained left hamstring.