The New England Revolution in the Eastern Conference and the Colorado Rapids in the Western Conference have byes this weekend and will make their post season start next week in the conference semi-finals.
Round one of the play-offs is spread across five days and it begins on Saturday with two much-anticipated fixtures.
There will be two more games on Sunday, one in each conference. After a day off on Monday the final first-round games are set for Tuesday.
The second round starts on Thursday as Colorado Rapids play host to the winner of the Portland Timbers/Minnesota United match. Meanwhile New England waits to host the winner of NYCFC against Atlanta United.
Rivals reunited as Union take on Red Bulls
The play-offs get started Saturday afternoon as number two seed Philadelphia Union host seventh seed New York Red Bulls. This season the teams met three times with the last two encounters ending in 1-1 draws. Union won 1-0 at home back in May while both of the draws came at the Red Bull Arena.
Union boast a terrific defensive record having posted 12 clean sheets this season and only conceding 35 goals.
Jack Elliott and Jakob Glesnes anchored the defense in 39 of the 40 games this season and Jamaican keeper Andre Blake returns after some big saves in his nation's 1-1 draw against the United States on Tuesday.
The Red Bulls go into the play-offs in good form having lost just one of their last 12 outings. Patryk Klimala is the man to watch having scored eight goals and produced six assists this season.
According to Planet Sport Bet, the Union are 11/10 to win while New York Red Bulls are 12/5.
Goals galore potential in New York
After playing home games in multiple places again this season, New York City FC get to return to Yankee Stadium for the play-offs. They have made the stadium their fortress with just six losses in their last 70 games at the world-famous baseball venue.
Fans will be allowed in full force for Sunday's tilt and the Pigeons are counting on boisterous support against an Atlanta team used to getting more than 50,000 fans for their home games.
Atlanta's attack has been fantastic of late with Josef Martinez rejuvenated after injury and flanked by Ezequiel Barco and Luiz Araujo.
New coach Gonzalo Pineda switched Atlanta to a back three and deployed wing backs which allowed United to find their offense after struggling under Gabriel Heinze early in the season.
For NYCFC the attack goes through MVP candidate Valentin Castellanos who scored 19 goals this season. Maxi Moralez led the team with 11 assists while the defense revolves around James Sands and keeper Sean Johnson who has nine clean sheets this season.
These teams met two times in the regular season, once in each stadium. NYCFC won at home 1-0 in June and the teams drew 1-1 in Atlanta last month. Planet Sport Bet has NYCFC 4/6 to win with Atlanta at 7/2 and a draw is 11/4.