Twenty-four teams from the United States, Mexico, Canada, Central America and the Caribbean began competing for the regional crown last summer. Next came the 16-team group stage, which wrapped up in October. Now it's on to the quarterfinals, the "knockout phase," where eight teams meet in four elimination series starting this week.
So the possibility always exists that a team undergoes significant turnover in the four-month interim -- which is precisely what has happened to the Columbus Crew.
Columbus is one of two MLS sides remaining in Champions League, now facing an uphill climb as a bunch of new faces oppose reliably steady Real Salt Lake. Still, the prize at the end is a spot in the FIFA Club World Cup.
Here is a look at all four quarterfinal matchups:
First leg: 8 p.m. Tuesday, Real Salt Lake at Columbus
Second leg: 10 p.m. March 1, Columbus at Real Salt Lake
The contrasts are stark. Real Salt Lake is perhaps the most stable of MLS teams, getting set to punch away in 2011 with pretty much the same core that won MLS Cup two years and ago and made such a fashionable account last year. Meanwhile, a roster in serious flux couldn't possibly come at a worse time for Columbus.
Gone are longtime Crew staples Guillermo Barros Schelotto, Frankie Hejduk, Brian Carroll, Adam Moffat and Gino Padula -- essentially the heart of the side that captured MLS Cup 2008. Others are gone, too, like forwards Jason Garey and Steven Lenhart. Plus, the Crew is dealing with injuries to Eddie Gaven, Danny O'Rourke, Shaun Francis and Dilly Duka. All are likely 2011 starters when healthy, but their status remains in question for Tuesday's first leg. Coach Robert Warzycha admitted that age-related roster turnover was further complicated by the expansion draft and by the league's re-entry draft.
"There were more changes than we anticipated," Warzycha said. "I'm not saying that's good, I'm not saying that's bad. We just have to do what we can."
So several players need to graduate this year from JAG status ("Just a guy") to game-breaker status, and fast. That means names like Robbie Rogers, Emmanuel Ekpo and Andy Iro, men long on potential but still short on full arrival. The time is here especially for Rogers, who is just 23 but already entering his fifth season at Crew Stadium. He has just two goals and five assists over 42 regular season games in the last two years, hardly enough for a primarily offensive presence.
Warzycha said Rogers has been more of a "track star" much of his career, and he wants the fringe U.S. international winger to become more of a "soccer player." Tuesday would be a great place to start.
Either way, the Crew will make things tough, especially in Ohio, where game time temperatures in the high 20s, possible snow flurries and a frozen or bumpy field could hammer RSL's possession game. With good servers for Columbus hitting balls to Chad Marshall and Iro, set-piece plays and determined defense seem the home team's best way forward.
The more technical Real Salt Lake may not be at its tiptop best so early. Still, Kyle Beckerman, Will Johnson, Javier Morales and Andy Williams could easily overwhelm a lesser-tested Crew midfield, where the important holding position looks highly unstable.
Real Salt Lake's players were bitterly disappointed at last year's first-round MLS playoff elimination. A longer march through this year's postseason and a spot in the FIFA Club World Cup would surely help atone for this confident group.
"This year, there's so much out there for us to win, it's real easy to keep everybody motivated," Beckerman said last week after a preseason workout in Arizona. "It had to be intense right from the start. Most of the time, when the preseasons are longer, you can take the first two or three weeks and ease into it a little bit. This gave us something meaningful to look forward to right off the bat. For me, I was looking forward to it. It was a good change."
First leg: 10 p.m. Tuesday, Santos at Cruz Azul
Second leg: 8 p.m. March 1, Cruz Azul at Santos
Five-time CONCACAF champion Cruz Azul has things moving in the right direction once again, currently second among six teams in the Group 3 of the Mexico's Clausura. That includes a 2-1 win over Atlas on Saturday. Emanuel Villa is the danger man of the moment, striking for his team-leading fourth goal of the spring campaign Saturday. The Argentine has scored at a rate of about once every two matches since coming from Derby County in 2009.
As always, Gerardo Torrado is the Cementeros' heart and soul; He's been a holding midfield staple for the Mexico City side since 2005.
Santos (3-3-1 in the Clausura) travels to Estadio Azul in Mexico City off a hugely disappointing loss at home to Querétaro on Saturday. Queretaro had previously captured all three points in only one game of six.
To make matters worse, Argentine coach Ruben Romano was sacked Monday after he criticized the team's fans for jeering his players. Newspaper photos had shown Romano making a finger gesture as he was leaving the pitch and facing the stands at the end of the Querétaro match.
First leg: 8 p.m. Wednesday, Monterrey at Toluca
Second leg: 8 p.m. March 2, Toluca at Monterrey
Perhaps the Guerreros of Santos Laguna weren't the only ones guilty of peeking ahead to this week regional competition.
No team was in better form than Toluca going into the weekend, undefeated in six matches with just one goal conceded in the Clausura before Sunday's 3-2 loss at Necaxa. Plus, Toluca has a big match ahead this Sunday at famed Club America.
Still, this represents huge opportunity for Toluca, based in Mexico's eighth largest city. A club from Mexico will definitely be in the Champions League final, given the bracket breakdown. A place in the FIFA Club World Cup would certainly be a grand day for Toluca and its popular midfielder Sinha, who has appeared 49 times for Mexico.
Monterrey is mid-pack in its Clausura grouping. But Chilean striker Humberto Suazo and inform setup man Dario Carreño can certainly make a difference. Suazo has five goals in seven matches this year, although the Chilean injured his shoulder against Tigres on Saturday and could miss Monterrey's next two games.
First leg: 8 p.m. Thursday, Olimpia at Saprissa
Second leg: 8 p.m., March 3, Saprissa at Olimpia
These are the power brokers of their respective countries, so it's odd that both have fallen on some hard times lately in domestic play. The Costa Rican giants didn't even qualify for their country's playoffs last year, although they did successfully negotiate Champions League group play.
Olimpia has won just once in its last five in the Honduran Primera division going into Monday's match with rival Marathon.
Meanwhile, Saprissa's Mexican manager Juan Manuel Alvarez made things sound downright dire when he told a Honduran newspaper that his team is lacking even the simplest of elements at the moment. Still, Champions League offers an escape hatch of sorts for both clubs; the winner here faces an MLS side in March that could be distracted by its league season, which opens about the same time.