Changes are afoot for the CONCACAF Champions League starting with the 2012-13 edition of the tournament, and they’re the sort that could have a profound effect not only on fixture congestion, but on the future of the burgeoning rivalry between MLS and Mexican Primera División sides.

Starting this summer, the two-leg preliminary round – in which 16 teams would face off in a home-and-home series – has been eliminated. Instead, all 24 teams in the event will be drawn straight into the group stage. Each of the eight groups will have three teams, and MLS and Mexican sides can’t be drawn into the same group.

Each group winner will then advance to the quarterfinals, which proceed unchanged from previous versions of the event.

"This new format will streamline the first phase of the competition," CONCACAF acting general secretary Ted Howard said in a press release. "It will alleviate schedule congestion on both domestic and international calendars."

The teams will be distributed into three categories for purposes of the draw:

Category 1: Mexico 1 & 2, USA 1 & 2, Costa Rica 1, Guatemala 1, Honduras 1, Panama 1

Category 2: Mexico 3 & 4, USA 3 & 4, Canada 1, Costa Rica 2, El Salvador 1, Honduras 2

Category 3: Belize 1 (pending approval of suitable stadium), El Salvador 2, Guatemala 2, Nicaragua 1, Panama 2, Caribbean Football Union 1, 2 & 3

Teams from the same country can’t be drawn into the same group, though thanks to the pan-nationalism of MLS, there is a 75 percent chance that Canada's CCL representative will be drawn into a group with one of its MLS brethren.

The new group stage comprises 48 matches. It will begin at the end of July and run through mid-October.

The four US representatives have already been decided, with the LA Galaxy and Seattle Sounders in Category 1 and the Houston Dynamo and Real Salt Lake in Category 2. The winner of the Nutrilite Canadian Championship — contested between Toronto FC, the Montreal Impact, the Vancouver Whitecaps and FC Edmonton of the NASL — could possibly add a fifth MLS club to the party.

The 2011-12 edition of the CCL resumes with the quarterfinal round on March 6. Three MLS teams survive, with Seattle facing down Santos Laguna and LA taking on TFC.