A smile that has gotten more notice than his slider became a little forced yesterday as reporters began to approach Rodrigo Lopez in the Orioles' clubhouse.

He knew the story angle and decided to step off it like a pitching rubber.

Lopez will be facing his old team tonight - the one that let him go after the 2001 season. The one that calculated all the prospects that had moved ahead of him in the organization and deemed him expendable.

The one wishing it could reverse that decision.

Lopez has emerged as the Orioles' strongest All-Star candidate by going 6-1 with a 2.51 ERA that ranked second in the American League before last night. He's joined hands with Travis Driskill to hold together a starting staff that seemed ready to crumble not long ago.

With the new interleague format, Lopez will pitch against San Diego for the first time since making his major-league debut with them two years ago. He went 0-3 with an 8.76 ERA in six starts, allowing 40 hits in 24 2/3 innings and looking like an impostor compared to what the Orioles have seen this year.

Maybe the Padres were justified in turning him loose. And maybe Lopez has a little extra incentive going into tonight's start.

If it's true, he's not telling.

Lopez, 26, politely declined to be interviewed yesterday if the subject involved the Padres. He broke into a smile, then broke off talks, saying he'd wait until after the game to reminisce.

In the other clubhouse, the Padres were preoccupied with roster moves. They sent one of their top pitching prospects, Dennis Tankersley, to Double-A Mobile after his abbreviated start in Monday's series opener.

They also expressed remorse in letting Lopez get away.

"We had a lot of young guys that were kind of coming and we thought they were probably ahead of him. It looks as if we were wrong," said Kevin Towers, the Padres' scouting director for two years before becoming general manager in 1995.

"He's having a lot of success here, so our read was definitely wrong. He's definitely better than we thought."

The Orioles signed Lopez as a minor-league free agent in November and felt justified each time the latest winter league stats were passed around. He went 10-2 with a 2.49 ERA for the Culiacan Tomato Growers, and won all five postseason decisions.

"He's a late bloomer," Towers said. "It sounds like his velocity is much better now. When he was with us, he was 89, 90, 91. They say now he's 92-94, and that makes a big difference.

"It's a great job on the Orioles' part. I'm happy for him. He's a great kid."

But how will the kid react when placed in front of the family that abandoned him? Orioles manager Mike Hargrove noted that catcher Geronimo Gil began to press against the Los Angeles Dodgers, who traded him last year.

Asked how a manager prevents this from happening, Hargrove said, "You don't. You've just got to go out and trust that they'll settle down and do their jobs and not try to be anything more than they are.

"If he wasn't a little more excited about playing against his old team, you might have to question whether he has a heart beating in his body. We all have done that. You've got to find a way to get by it."

Sun staff writer Joe Christensen contributed to this article.