A tentative version of the Washington Nationals' home schedule for next season holds, finally, what fans clamored for this year, but didn't get: games against the Baltimore Orioles at RFK Stadium.

The Orioles, the only team to vote against the relocation of the Montreal Expos to Washington last fall, are scheduled to play a three-game series in the District the weekend of May 19-21, 2006, according to a baseball source with knowledge of the Nationals' schedule.

The schedule must be approved by the 30 clubs and could change, according to the source, but that is unlikely. The Nationals also will play a three-game series at Oriole Park at Camden Yards. Dates for that series were unavailable. Interleague play typically takes place in May and June.

Baseball officials have acknowledged that the Nationals and Orioles, natural geographic rivals whose stadiums are roughly 35 miles apart, would play each other in a home-and-home format next year and beyond. The clubs didn't play this season, the Nationals' first in Washington, because the schedule was largely in place by the time baseball officials announced the Expos would move to the District last September.

"That's going to be our natural rival," Nationals President Tony Tavares said by telephone Friday. "This isn't a one-year thing. It will be an annual thing, as long as there's interleague play. It makes the most sense."

The teams from baseball's other two-team markets -- the New York Yankees and Mets, the Chicago White Sox and Cubs, the Los Angeles Dodgers and Angels and the San Francisco Giants and Oakland Athletics -- annually face each other in interleague play.

The Nationals' division, the National League East, will match up against the Orioles' division, the American League East, in interleague play in 2006. Washington is tentatively scheduled to host the New York Yankees for a three-game series the weekend of June 16-18, and also will host Tampa Bay. The Nationals will play road series against AL opponents Boston and Toronto. According to the Boston Globe, the series against the Red Sox in Boston will begin June 19, a Monday.

The Nationals' second season is tentatively scheduled to begin just as the first did -- on the road. This time, though, it will be on April 3 in New York against the Mets. The home opener also will be against the Mets; a three-game series at RFK Stadium is tentatively scheduled for Tuesday-Thursday, April 11-13.

The Nationals and Orioles played three times during the Grapefruit League exhibition season.