In a bizarre situation threatening to disrupt D.C. United's playoff plans, defender Diego Sonora probably will leave the club next week after its first-round series against the Miami Fusion to pursue a contract with a Latin American team.

Sonora's amended contract with Major League Soccer expires at the end of November, but he has received permission from MLS and United to leave at the end of this month to improve his chances of finding a new team. Even if he stays until the conclusion of the season, Sonora is almost certain not to return to United next year.

"My agent [Ruben Morales] is looking for a team," Sonora said following practice at United Park yesterday. "Mexico and Argentina are a possibility."

United won the first game of its best-of-three series with the Fusion last weekend at RFK Stadium and hopes to wrap things up Sunday in Fort Lauderdale, Fla. Sonora, 30, is expected to be available for that match and, if necessary, Game 3 next Wednesday in Washington. But if United advances to the Eastern Conference finals, he probably won't be around.

"You hate to see this happen at this particular time," Coach Thomas Rongen said. "Right now I'm handling it as Diego being one of 23 players on our roster. Our objective is to get the best 11 players on the field, and if Diego fits in that picture, he will play until the day we find out that he, in fact, is going to move on, which right now seems to be at the end of this month."

MLS--which, under its single-entity structure, owns and primarily negotiates all player contracts--has offered to extend Sonora's contract, but, according to reports in the U.S. Spanish-language media, at a significantly lower salary than the estimated $140,000 he's earning.

Sonora, acquired in a trade with New York/New Jersey last winter to fix United's problems at right back, started 27 of 32 regular season games and had one goal and five assists. He played all 90 minutes in United's 2-0 playoff-opening victory over Miami last Saturday.

"I think the league has made him a very credible offer," United President and General Manager Kevin Payne said, "but he apparently believes that he can do better elsewhere, and that's his right."

Ivan Gazidis, an MLS executive vice president who oversees contract negotiations, said he would not comment on the specifics of the offer. "At the moment we're in an uncertain situation with Diego," he said.

Confusing the matter, Sonora's initial contract with MLS was only good through the end of October because each of the previous three seasons ended by then. This year, however, the playoffs were extended and the championship game pushed back to Nov. 21. According to Payne, Sonora signed an extra document last spring to keep him under contract in case United's season continued into November.

Asked why the league doesn't make Sonora honor his amended contract, Payne said, "We don't want to stand in his way because he felt it would be almost impossible to find a new team if he waited past October."

However, a team source said: "There's no reason to keep him here. I mean, do you really want to count on a guy who doesn't want to be here?"

Sonora's teammates are aware of the situation and some understand Sonora's predicament after their own contract squabbles with the league.

"We want him to stay here and win a [championship] ring with us," defender Jeff Agoos said. "But he has got to do what's best for him and his family."

This week MLS signed United star forward Jaime Moreno to a multiyear contract extension for the league-maximum salary of about $250,000. Several other D.C. starters also signed long-term deals in the past year.

If Sonora leaves, Rongen said he is not too worried about finding a replacement during the playoffs. Reserves Carey Talley and Geoff Aunger played well all season when starters were absent, and the club is hoping all-star Carlos Llamosa will be able to return from a sprained knee ligament in a few weeks.

"We've overcome losses all year," Rongen said. "You like to get to a point where one unit can gel in the playoffs, but this is something we obviously did not anticipate and cannot control. It's not an ideal situation, but we will roll with the punches."

In anticipation of Sonora's departure, Payne said he already "has a few thoughts" about whom he would like to bring in to fill Sonora's foreign-player slot next year; each team is permitted four on the roster. His preference is another Latin American, he said.