MLS has turned down D.C. United’s request to play all 17 home matches at its new stadium over the last four months of the season, an expected decision as the league prepares to finalize the 2018 schedule.

But in a victory for the organization, United will probably have to play only two games at alternative home sites — one in March and one in April — before moving into Audi Field in late June. Initially, the league was proposing as many as four, deeply cutting into the club’s revenue projections at the new venue.

The Insider has learned the home opener will take place March 17 — the third weekend of the season — against the Houston Dynamo at a venue to be determined next month. Two prime options are out of the running because of previously scheduled events: Navy-Marine Corps Memorial Stadium in Annapolis (Navy men’s lacrosse) and Richmond’s City Stadium (Washington Spirit friendly).

Maryland SoccerPlex in Montgomery County has gained late support to stage the game, despite a 5,200-seat capacity deemed too small for MLS regular season purposes. The league would have to approve such an arrangement. (United averaged 17,904 at RFK Stadium this year.) The club has played many U.S. Open Cup games there over the years.

For various reasons, United has ruled out using FedEx Field, Nationals Park, Byrd Stadium in College Park and M&T Bank Stadium in Baltimore. The Baltimore Orioles showed interest in hosting United at Oriole Park at Camden Yards, but talks have not progressed. United has also explored the possibility of using the University of Maryland’s Ludwig Field (7,500 seats), the University of Delaware’s football stadium and WakeMed Soccer Park in suburban Raleigh, N.C.

The club would return to RFK Stadium, its home for 22 seasons, “only in the case of emergency,” one source said. In the wake of United’s last appearance there in October, however, it’s unclear whether RFK would even have a suitable field ready for an early-spring match.

With Annapolis and Richmond out of the mix for the first home match, RFK might re-emerge.

In all likelihood, D.C. will probably end up playing the off-site home match in April in Annapolis.

Audi Field is on schedule to open in late June, club officials said. United had hoped the league would fit the entire home slate into a window between mid-summer and late October. However, scheduling complications and concerns about an unfair late-season advantage apparently influenced MLS’s decision.

United will open the 34-game slate March 3 at Orlando City, sources said, and play on the road the following weekend — if it does not receive a bye. (With Los Angeles FC becoming the 23rd team in 2018, one will have to sit out each weekend.)

Overall, D.C. will probably have two off-site home matches and about 10 away games before christening Audi Field.

MLS is tentatively planning to announce all home openers this week and unveil the complete schedule sometime next month.