The Union will open the season against the host Portland Timbers on Monday, March 12.
Game time is 9:30 p.m. at Jeld-Wen Field with coverage on ESPN2, ESPN Deportes and ESPN3.
The match will be just the 11th Monday game in MLS history. The Union are 0-1-1 against the Timbers, having dropped a 1-0 decision in Portland last May and playing the Timbers to a 0-0 draw at PPL Park in September.
The Union returns to PPL Park to open the home portion of its season on Sunday, March 18. The opponent and time are to yet be announced.
The league announced four opening weekend matchups.
Sat., March 10 - Vancouver Whitecaps FC vs. Montreal Impact, 6 p.m. ET on TSN
Sun., March 11 - FC Dallas vs. New York Red Bulls, 3 p.m. on NBC Sports Network
Sun., March 11 - Chivas USA vs. Houston Dynamo, 7 p.m. ET on Galavision
Mon., March 12 - Portland Timbers vs. Union, 9:30 p.m. ET on ESPN2, ESPN Deportes & ESPN3