Meanwhile, Ignacio Piatti, Wilmer Cabrera remain uncertain about what their futures hold.
Toronto (13-10-11) leapfrogged the New York Red Bulls and D.C. United to finish fourth in the East.
The Sounders (16-10-8) will host a first-round playoff game against FC Dallas.
With the win, LAFC set an all-time record of 72 points in a season. Vela’s hat trick gave him 34 regular-season goals.
Call him ‘Mr. October’ because Dairon Asprilla has sent the Timbers to the playoffs.
Despite a strong early start, an injury to Robin Jansson shook the team as it fell to the Fire in its final game of the year.
D.C. United watch a home playoff game slip away by failing to score against the worst team in MLS.
Sunday’s 2-1 loss means the Union will enter the playoffs with one victory in their last five games.
The Five Stripes and Revs will meet again in the first round of the MLS Cup playoffs.
Real Salt Lake City clinch first-round home game in MLS Cup with 1-0 victory over Vancouver Whitecaps.