The National League's process for deciding where to locate the two expansion franchises it will add in 1993 moves into a new stage today in New York, where the expansion committee begins to hear presentations from 18 prospective ownership groups representing 10 cities.

Representatives of Denver, Buffalo, Miami and Sacramento, Calif., will make their pitches today. Washington's two groups are scheduled for Wednesday, along with Orlando and Charlotte. Tampa-St. Petersburg and Phoenix will be heard Sept. 28.

The group seeking a team for Northern Virginia will meet with Virginia Gov. Douglas Wilder. Mark Tracz, the principal organizer, said yesterday the group plans to brief Wilder on its activities and is hoping to obtain a letter of support it can present to the expansion committee.

Public support is just one factor the committee will measure, chairman Douglas Danforth of the Pittsburgh Pirates said last week. Stadium arrangements, financial projections and the individual investors are the other main factors.

"We will be very familiar with the cities before we get there," said Danforth, who is joined on the committee by NL President Bill White, the New York Mets' Fred Wilpon and the Houston Astros' John McMullen.

Thus, the formal part of each presentation is to last only about 30 minutes. The groups, which are to be represented by no more than five people, will then face questions.

Danforth said that once all the presentations have been completed, the committee may seek additional information before reducing the field of candidates to four or five finalists by the end of the year.

One issue the committee may have to examine is the home video agreement Major League Baseball and the New Jersey-based Phoenix Communications Group recently concluded with Blockbuster Entertainment. Blockbuster is owned by Wayne Huizenga, leader of one of three groups seeking a team for Miami. The agreement will make Blockbuster the exclusive retailer and rental outlet for highlight tapes of the World Series, All-Star Game and others that are produced for baseball by Phoenix.

"Whether it's a conflict, that's something that has to be a examined," said NL spokeswoman Katy Feeney. "I don't think it gives them {Huizenga's group} a jump up or a jump down."

"Expansion is far too big a situation to be affected by a video deal," said Don Smiley, an assistant to Huizenga who also serves as vice president of his South Florida Big League Baseball Inc. "It was a good deal for Blockbuster. It was a good deal for Major League Baseball. It's a totally unrelated development as far as our quest for an expansion team is concerned."