Starting in the Summer of 2017, the CONCACAF Champions League will contain 31 teams in a new format of dual tournaments. The first tournament will be contested between 16 clubs from the Caribbean and Central America. That winner will enter the second phase of the new CCL in 2018 competing against MLS, Liga MX and a selection of other CONCACAF clubs in a straight knockout tournament starting in February 2018 and ending in May of that year. That winner would qualify for the Club World Cup in December.
In short, CONCACAF has eliminated the group stage while containing the tournament in a much smaller time frame and adding a round that could pit MLS and Liga MX teams against one another. It’s believed that the Sounders will compete in the 2018 version of the tournament, but it is not been 100 percent confirmed.
For MLS teams, this will mean the potential for up to eight games in the new format (two in each of the four rounds), but as few as two. The most recent format maxed out at 10 games for MLS sides (four in the group stage and as many as six in the knockout) and guaranteed at least four. Prior to that, the structure could lead to 14 games (two in qualification, six in the group stage and six in the knockout). This is a further reduction of games for MLS and Liga MX teams, especially against lower quality champions from around the region. A Caribbean or Central American side that wins phase one could wind up competing in 16 CCL games, but spread over a much longer time.
The biggest benefit of the change is roster continuity within the tournament. Now, when an MLS team qualifies they will finish their CCL journey within a single year of qualifying. Under the old format the MLS offseason separated the group and knockout stages.
It is not yet clear how US Soccer, the Canadian Soccer Association and the Federación Mexicana de Fútbol Asociación will choose their participants for 2018, as they will have two sets of qualifiers.
CONCACAF’s statement on this says;
Clubs that have already qualified for the 2017/18 edition of the Scotiabank CONCACAF Champions League maintain guaranteed participation in one of the two tournaments of the upcoming club championship season; which tournament is decided based on aggregate results and the indexing of the respective leagues.
There is no further clarification as to when 2016’s MLS qualifiers - Seattle Sounders (MLS Cup), FC Dallas (Supporters’ Shield), New York Red Bulls (Eastern Conference winner), Colorado Rapids (best record after dual qualification of FCD) and Toronto FC (Canadian Championship) - will enter international competition.
The Seattle Sounders qualified for the 1996 CONCACAF Champions Cup and the 2010-11, ‘11-12, ‘12-13 and ‘15-16 CONCACAF Champions League tournaments. By winning MLS Cup in 2016 they will be in a version of the CCL.