New York RB - a point clear in the East - have the weekend off after rescheduling their clash against Montreal Impact to October 8 due to the latter's CONCACAF Champions League semi-final commitments, while New York City are one of two teams with the bye alongside Columbus Crew.
New York RB's rescheduled fixture has paved the way for United and Orlando City to battle it out for top spot, when the two teams kick-off the round at Florida Citrus Bowl on Friday.
Hosts Orlando City are fourth in the East following their entertaining 2-2 draw in Montreal, two points behind the Red Bulls and one adrift of second-placed United, who edged reigning MLS Cup champions Los Angeles Galaxy 1-0 last week.
Kofi Opare played a key role for United as the Washington franchise beat the Galaxy for the first time in seven seasons.
Opare completed 85 minutes in his first league appearance for United since arriving from Los Angeles in July last year, replacing injured defender Steve Birnbaum, who is reportedly set to miss up to six weeks due to a sprained left ankle.
"He hasn't had a lot of minutes for us or in the league," said United coach Ben Olsen. "But from what I've seen of Kofi, he's a gamer. He has a mentality that he can step in and do the job, and [against the Galaxy] I thought he was great. It was a good match-up for him."
Western Conference pacesetters FC Dallas can preserve their unbeaten record with a result at the struggling Portland Timbers on Saturday.
Dallas - one of four undefeated teams in the MLS alongside New York RB, Real Salt Lake and Colorado Rapids - make the trip to Providence Park one point clear of Vancouver Whitecaps atop the West after winning three of their opening four matches.
As for the Timbers, they are bottom in the West on goal difference following three draws and one defeat.
Elsewhere on Saturday, Toronto welcome back star duo Michael Bradley and Jozy Altidore from international duty for their trip to Chicago Fire.
New England Revolution, who returned to winning ways last week, are away to the Rapids, Seattle Sounders entertain Houston Dynamo, while the Whitecaps play host to the Galaxy.
On Sunday, San Jose Earthquakes and RSL go head-to-head at Avaya Stadium.
Sporting Kansas City play Philadelphia Union minus United States international Graham Zusi, who will miss the next two matches due to a hamstring strain.
