Once again, professional soccer in Washington faces a deadline Monday. Once again, barring a late breakthrough, that deadline will not be met.

Last Monday, NASL owners granted Washington and Rochester one-week extensions to try to come up with financial backing to revive their terminated franchises. Since then, Steve Danzansky, Diplomat president, has spoken with several more prospective owners, but none has come forward with the necessary funds.

"We're about where we were Monday," Danzansky said. "We're still talking to people, still trying to work something out."

An effort headed by former Diplomat publicity director Ronnie Gold to get people to pledge to buy season tickets for 1981 to show league owners that Washington should have a team, has produced more than 5,000 names in about 10 days. But those names do not translate into cash and it will take close to $3 million to revive the Diplomats, who technically ceased to exist on Nov. 24.

But now, with the third deadline 24 hours away, Danzansky does not sound terribly optimistic. "We've all been riding his roller coaster the last few weeks," he said. "I've had so many people in and out of my office the last couple of weeks, it's been unbelievable. But we still haven't made that one breakthrough we all thought we were going to be able to make."