Season Description The 2015 Major League Soccer season featured 20 total clubs (17 based in the United States, 3 based in Canada). The regular season was held from March 6 through to October 25, whereas the MLS Cup Playoffs began on October 28 and ended with MLS Cup 2015 on December 6. The defending MLS Cup champions were the LA Galaxy, while Seattle Sounders FC were the defending Supporters' Shield winners. It was the first season for expansion teams Orlando City SC and New York City, who both joined the Eastern Conference, while both the Houston Dynamo and Sporting Kansas City moved from the Eastern Conference to the Western Conference. Chivas USA folded at the end of the 2014 season.