OAKLAND, Calif. -- Of all the mysteries surrounding the Orioles' 19-30 season, none is as vexing as the search for who filled Scott Erickson's lead pitches with helium.

A month of steady recovery fizzled yesterday as Erickson was rocked for seven runs in 2 2/3 innings by the Oakland A's and their nickel offense. What ended as an 11-5 loss was largely decided in the first two innings as the A's doubled four times and received a two-run homer from gimpy-legged designated hitter John Jaha, all against Erickson (1-7). The loss evened the Orioles' record at 3-3 on their nine-game road trip, but extended what has been a troubled season for their No. 2 starter.

"I've never been 1-7," Erickson said. "That's where I'm at right now. It's frustrating. I feel great; I feel healthy; I feel prepared every time I take the field. Things just aren't working out."

The pounding mystified manager Ray Miller. Based on the day's opponent and Erickson's strong performance in the bullpen before the game, Miller expected another notch in the starting rotation's recent string of solid starts.

"Cool air. Heavy grass. Not necessarily a power-type lineup," recited Miller.

Naaaah.

Before losing their second series of the season to the surprising 26-24 A's, the rotation had compiled a 3.72 ERA in the previous 12 games, including nine quality starts and only 25 walks in 82 1/3 innings. The Orioles enjoyed a 3.14 ERA on the road trip and had received a complete game from Mike Mussina, their third of the season.

For May, the Orioles had pitched to a 4.78 ERA, not brilliant but certainly better than the 6.49 abomination that wrecked their April.

Then yesterday happened. The league's least imposing lineup crushed pitch after pitch after pitch. The two hardest-hit balls off Erickson may have been Olmedo Saenz's lineout to center fielder Brady Anderson in the first inning and Matt Stairs' drive that lifted right fielder Albert Belle off his feet in the second. Constantly concerned about preserving his bullpen, Miller may have been more worried about the safety of his fielders. Erickson got only two ground-ball outs.

"That's not a very good performance out of Scotty, that's all," said Miller.

Whatever the cause, the innings monster remains an inconsistent road animal. The last two seasons he is 8-11 with a 5.06 ERA away from Camden Yards. He has won only three of his last 13 road starts and just one in six attempts this season: a May 9 five-hit shutout of the Detroit Tigers. Miller and pitching coach Bruce Kison have tried altering his routine between starts, starting him on short rest and helping him adjust mechanics that decayed during spring training.

The latest loss represented a disturbing setback as the A's raked three pitchers for 16 hits, eight for extra bases.

Until Saturday night's 7-5 Orioles win, the A's hadn't managed 10 or more hits for 12 consecutive games. Yesterday marked the first time in 22 games they scored double digit runs.

"This is disappointing because we'd been pitching well," Miller said. "You come to the park expecting it. You should be able to hold this team down. Most people do."

Starved for wins, Erickson still contributed to the recent turnaround. In his five May starts before yesterday, Erickson was 1-1 with a 3.72 ERA, a shutout and four starts of at least seven innings. Erickson had also walked only five in his last three starts covering 20 1/3 innings. Yesterday's beating shot Erickson's ERA to 6.75. Only twice before had he allowed more than the 11 base runners who reached against him in his second-briefest appearance this season.

"I got pitches up and they smoked them. They came out of their shoes. They came out swinging the bats and were aggressive. It paid off," Erickson said.

The Orioles answered with three home runs, including the fourth by designated hitter Harold Baines in five games. B. J. Surhoff homered for the second consecutive game. However, it was no match against the A's, who got hits from every regular, including three from shortstop Miguel Tejada, and three doubles in the first inning off Erickson.

Erickson tried fastballs in the first inning and sliders in the second. Both pitches stayed up and the A's feasted for an offensive breakout that had them leading 2-1 before their first out, 5-1 after the first inning and 7-1 before Miller rescued Erickson with two outs in the third inning. With the Orioles headed for a three-game series against the slugging Seattle Mariners, the early exit was doubly disturbing.

"Mechanically speaking, I'm where I need to be. I feel like I'm throwing the ball with good velocity. I made a few bad pitches and that was it," Erickson said. "I'd like to soak up a few innings for the 'pen going into Seattle. But Ray decided not to. I really have nothing to argue about."

Theories for Erickson's lapse remain in short supply. Miller did not notice a return to the poor mechanics that ruined Erickson's April. Catcher Charles Johnson appeared similarly baffled.

"It's frustrating for me as a catcher. You try to do the best you can to call a game for him. A guy with his kind of stuff to see him get hit that way is very frustrating," Johnson said.

There was little subtlety to it. Tony Phillips led off the A's first inning with a smash Erickson couldn't hold. Tejada then rifled a ground-rule double over Anderson's head in center and the beating was on. Stairs lined a double to right field that erased the Orioles' 1-0 lead forged by Baines' infield single.

"I can't make any excuses. I went out there. I was ready. I should have caught the first one. The second one was a good pitch but he got under it and lifted it 400 feet to center," Erickson said. "All of a sudden we're in a hole and I have to make a perfect pitch to keep them off the board."

Perfection was in short supply on both sides as A's starter Mike Oquist couldn't last the five innings to take the win. Reliever Brad Rigby survived the longest of any pitcher, lasting 4 2/3 innings while surrendering bases-empty home runs to Baines and Surhoff. Baines' homer was the 359th of his career, tying him with Johnny Mize for 48th all-time.

Rigby's most critical pitches came in the fourth inning when he entered a 7-3 game with two on and one out. He got Surhoff to pop out to second base and Belle to ground out. The Orioles never again put the tying run on deck.

Orioles tonight

Opponent: Seattle Mariners

Site: Kingdome, Seattle

Time: 8

TV/Radio: HTS/WBAL (1090 AM)

Starters: O's Sidney Ponson (5-3, 4.20) vs. Mariners' Jamie Moyer (5-4, 5.50)

Pub Date: 5/31/99