SAN FRANCISCO - This could have been awkward.

The Orioles already had a second baseman. Granted, Jerry Hairston hadn't played up to expectations early in the season, but he was starting to come around, and here they were promoting Brian Roberts from Triple-A Rochester to start at second base.

Basically, Hairston had been relegated to the bench. Few could have blamed him for showing some resentment, but he never showed any toward Roberts.

"I told Brian," Hairston said, ' "Obviously, you're my teammate, and I want you to succeed.' "

"I'll tell you," Roberts said. "It's really helped me a lot the way that he's handled it. It's helped me relax a little bit and know that there's not somebody on the bench who hates me because I'm out there. And I hope it's the same way when he's out there, that he knows that I want the best for him."

With that part resolved, Roberts had the chance to just play.

He tried not to think about how this was really his first big chance. Last season, when shortstop Mike Bordick went down with a shoulder injury, the Orioles rushed Roberts to the big leagues after two half-seasons in the minors. They weren't expecting much, and even though he hit well for stretches, his glove work deserted him at shortstop.

In a span of 20 games, he committed 11 errors.

"He caught some bad luck," said Orioles bench coach Sam Perlozzo. "It seemed like every time he made a mistake, the other team scored runs. That compounds it. It makes you a little more jumpy, and it snowballed on him."

With Perlozzo's help, Roberts went about improving his defense, using better footwork to get in front of more balls and turn more double plays. The Orioles saw the difference during the spring, but with Bordick healthy and Hairston playing well, they sent Roberts to Rochester for seasoning.

Eight weeks later, Roberts was back. Hairston hit .156 over his first eight games, strained his left groin, lost his leadoff job and never seemed to regain manager Mike Hargrove's confidence.

When Roberts started his first game at second base, May 23, Hairston had a .239 average. Over his first eight games, Roberts hit just .179.

"I was definitely out of sync," Roberts said. "It was weird because it was almost like I couldn't get it to stop, and I didn't know how. Some of the other guys said, 'Look, relax. Go out there and play and everything will be fine.' "

Soon, they were right. Roberts began doing exactly what the Orioles thought he could do: get on base and score runs. Entering today, Roberts had 87 at-bats compared with 154 for Hairston, but Roberts had more walks (12 to 11), three fewer runs (14 to 17) and one less stolen base (7 to 8).

"There are different ways to be a run producer," Hargrove said. "A lot of times you don't see young players do that. They kind of flounder around trying to figure out what they're trying to do, even though deep down they know what it is they're supposed to do.

"Brian does have base-stealing ability. Not just the raw speed, but the ability to steal a base when everybody's looking for him to go. And there aren't many base stealers who can do that. That's a real special gift."

Roberts has slumped again of late. A switch-hitter who normally hits equally well from both sides, he entered today batting .103 from the left side and .296 from the right side. But his defense hasn't been a problem. He entered the weekend with just two errors, and Wednesday night in Arizona, he made two terrific plays - one to his left and one to his right.

Meanwhile, Hairston has seized the opportunities when he has been back in the lineup. Since Roberts' promotion, he's batting .279 (12-for-43 entering today).

Hargrove has used Roberts as the designated hitter five times, allowing him to put Hairston at second base and keep them both in the lineup. Without the DH on this nine-game stretch of games in National League parks, Hargrove has played Roberts strictly against right-handed pitchers and Hairston strictly against lefties.

"I'm not in the business of burying anybody," Hargrove said. "Jerry's still a very good major-league player.

"I think it's been a good situation having them both here. I think they're pushing each other, and I know Jerry's been a better player since Brian's been here."

Team sources indicated they would trade Hairston or Roberts, likely in a package deal with a pitcher, for the right offer. But for now, the Orioles seem content keeping them both on the big-league roster.