Audi Field, a 20,000-seat venue in Southwest Washington, opened last month. (John McDonnell/The Washington Post)

D.C. United is engaged in talks with both a club team and a national team from Central America about friendlies this fall at Audi Field, people familiar with the negotiations said.

If deals are struck, United would play Honduran side Olimpia in late September and El Salvador’s national team in early October.

The purpose seems three-fold: provide playing time for secondary players at a time when Coach Ben Olsen is narrowing his lineup for the regular season’s stretch run; bring nonleague events to the new stadium in Southwest Washington; and increase outreach to the D.C. area’s large Central American community.

The first game would fall in an almost two-week gap in United’s schedule: After hosting the New York Red Bulls on Sept. 16, D.C. will not play again until Sept. 29 against visiting Montreal.

One of the proposed dates for the El Salvador match is a Wednesday (Oct. 3) after Montreal visits and before the Oct. 7 home game against Chicago. That international match, in particular, would not feature United’s regulars.

If the plan is finalized, El Salvador would visit the Washington area twice in a three-week span; it is already slated to play Brazil in a Sept. 11 friendly at FedEx Field.

The D.C.-El Salvador match would not likely take place within an official FIFA window and, consequently, would restrict Salvadoran player availability to some extent. Most Salvadorans in the player pool, however, are employed by domestic clubs, and the federation presumably would strike a deal with its teams to bring a select squad to Washington.

Olimpia, based in Tegucigalpa, is Honduras’s most decorated club with 30 domestic league titles since 1967 and Concacaf Champions’ Cup trophies in 1972 and 1988. The trip to Washington would probably fit between league matches Sept. 16 and Sept. 23.

United used to play midseason friendlies every year — opponents included, among others, Real Madrid, AC Milan and Paris Saint-Germain — but hasn’t scheduled any since facing English club Fulham in July 2014 in Jacksonville, Fla.

The international events are part of United’s increasing efforts to fill dates at $400 million Audi Field, which opened last month. The first non-MLS game will take place Saturday night when the Washington Spirit hosts the Portland Thorns in a National Women’s Soccer League match. On Labor Day, the University of Maryland and Virginia men’s teams will clash there.

The organization is in talks with Howard University about playing its homecoming football game at the venue starting in 2019, and is eyeing rugby matches, concerts and other college, pro and international soccer opportunities.

United officials said they did not want to comment on specific prospective events at Audi Field.