Clubs will play four fewer games, lose national team players for at least seven matches.
Megan Rapinoe's tiebreaking goal in the 82nd minute lifts top-seeded Seattle into the NWSL final against Kansas City.
Washington will play at Kansas City or Seattle in the playoffs next weekend.
After 13 years as a professional, the former University of Virginia star is preparing to step away from NWSL.
In the weekly print package, a look back at United's 3-0 loss at Real Salt Lake and other news and notes.
Yael Averbuch scored a sensational goal in stoppage time to defeat Chicago at Maryland SoccerPlex. Video:
Spain at RFK. El Salvador's arrival. U.S.-Nigeria tickets in Jacksonville. World Cup friendlies on TV. Reggae Boyz. D.C. United. Washington Spirit.
Spain in Washington. Xabi Alonso's thoughts. Copa America in D.C.? Mexico video. Today's friendlies. D.C. United stadium update. Washington Spirit signing.
David Villa signs with MLS. Spain arriving in Washington. Spirit wins again. Women's World Cup qualifying. Brazil tuneup. Post front page.
Former All-Met scores sensational goal in stoppage time in National Women's Soccer League match at Maryland SoccerPlex.