D.C. United celebrated late into the night Sunday in a banquet room at the team hotel in nearby Dedham, Mass., after winning its third Major League Soccer championship in four years. But after the cigars were extinguished, the champagne bottles collected and the goofy speeches made, United began to turn its attention to an autumn ritual not nearly as pleasurable as winning a title: figuring out who won't return next season.

Although United has been the most dominant team in the league's four-season history, it has a losing record against the league's meager salary cap.

Forward Raul Diaz Arce was traded after the 1997 season. Midfielder John Harkes was dealt and midfielder Tony Sanneh left for a big salary in Germany last offseason. A few others also have departed over the years for financial reasons.

This year, United apparently will lose two regulars--forward Roy Lassiter, MLS's all-time leading scorer, and Argentine defender Diego Sonora--for different reasons.

Lassiter is expected to be sent to the Miami Fusion this week to complete a midseason trade between the teams, but even if that deal were not in place, United might have had to consider trading him or someone else with a larger-than-average salary to stay under the cap.

Sonora's contract has expired, and he has said he probably won't accept the league's new offer. If he does, however, United will have to trade him, too, because of the salary cap.

"Every year players have to leave, and that's a shame," veteran defender Jeff Agoos said. "We shouldn't be penalized for being successful. Every year that happens. The league needs to do something so we can keep quality players--not just us, but other teams in our league. Maybe this comes with being successful, but I just don't think it is right. . . .

"The league can dismantle a team at the snap of a finger, and that's not really fair. The club's direction should be controlled more by the club and not by the league."

The salary cap for a 20-player roster was $1.635 million this season and probably will increase by only about $100,000 next year.

United gets hit particularly hard each year because as the team continues to win, its players ask for--and receive--significant raises from the league, which owns and primarily negotiates all player contracts. Forward Jaime Moreno signed a new deal last month, rookie forward Chris Albright's salary is expected to jump and reserve forward A.J. Wood is seeking a new deal after his contract expires on Dec. 31.

With Sonora leaving, United has an opening for another foreign player. D.C. saw some possible candidates when it played at the CONCACAF Champions Cup in Las Vegas--Honduran Jorge Caballero and Costa Rican Harold Wallace, for example--but the club probably can't fit either one under the salary cap.

Nonetheless, United appears to be in excellent position to chase another title. Carey Talley has developed steadily and could take Sonora's spot at right back, although he may be more effective in the central defense or defensive midfield. If Lassiter leaves, Wood--a Rockville native who scored eight goals this year--or the highly regarded Albright, who is recuperating from a knee injury, could start.

Most intriguing is whether 19-year-old midfielder Jose Alegria will be available. Alegria was impressive at spring training this year, but had to return to his native Peru while awaiting a work permit. United officials are cautiously optimistic that his paper work will be approved before the team reconvenes in Florida in February.

Off the field, the club expects to announce the sale of its operating rights soon and then sign a new lease to continue playing at RFK Stadium.

United Notes: By virtue of its MLS title, D.C. received an automatic berth in the 2000 Champions Cup in Las Vegas next winter. United finished tied for third this year and missed a chance at advancing to the inaugural world championships in Brazil. . . .

United is considering an exhibition tour in Bolivia early next year and has been approached about playing English club Newcastle next summer. . . .

United's victory parade begins at 11 a.m. Tuesday, starting at Third Street and Pennsylvania Avenue and finishing with a rally 10 blocks west at Freedom Plaza.