Kirk Sides/Icon SMI Bob Bradley faces a tough year, as he tries to rebuild the U.S. team and prepare for the Gold Cup. Bob Bradley faces a tough year, as he tries to rebuild the U.S. team and prepare for the Gold Cup.

It's not for nothing that the word "hangover" is often associated with the year that follows a World Cup. The emotional letdown that occurs for the players and coaches seems inevitable. But time, not to mention the next World Cup cycle, waits for no one, and 2011 is shaping up to be an important year for soccer in the U.S.

In 2007, the U.S. men's national team created some priceless momentum by winning the Gold Cup. U.S. manager Bob Bradley will try to duplicate that feat next summer while reshaping a squad that has some considerable holes to fill in its lineup.

The coming year is vital in other ways as well. Both the men's U-20 team and the women's national team will be vying for world titles. And MLS faces some developments and decisions that will be critical to its future.

With that in mind, here are the key storylines to follow in the U.S. as 2011 unfolds.

6. Hello, Portland and Vancouver

MLS got it right with the league's expansion in Seattle and Philadelphia. Can that enthusiasm be duplicated in the Pacific Northwest? So far, the signs are positive. Already, both Portland and Vancouver have topped the 10,000 mark in season-ticket sales, and the proximity to Seattle should allow for some healthy rivalries to emerge.

As for the teams themselves, Vancouver looks to have hit the higher notes so far with the players it has acquired, but with the SuperDraft and the opening of the international transfer window set for January, there are plenty of signings still to take place.

5. MLS's proposed schedule change

Will MLS really go through with the idea of switching to the international calendar: an August-through-May season? MLS commissioner Don Garber swears he's seriously considering it, despite the host of questions the idea raises. Will fans really turn out in cold weather in Kansas City, Toronto and Denver for humdrum regular-season games? (Not likely.) How much of a winter break will there be? (It seems two months, minimum, would be needed.) Is MLS really better off going up against the NBA as opposed to the NFL and college football to attract higher TV ratings? (Hard to say.) What will be the effect on the U.S. national team? (Good question.)

Granted, the change isn't imminent -- for 2011, MLS will commence its season in March like it did in 2010 -- but the issue will get plenty of attention and provocative debate as the year progresses.

[+] Enlarge Mike Zarrilli/Getty Images

4. The U-20 World Cup and U.S. player development

This is a big year for the U.S. U-20 national team and its coach, Thomas Rongen. The team will travel to Guatemala in April to participate in World Cup qualifying via the CONCACAF U-20 Championship. If all goes well, the U.S. will head to Colombia in late July for the U-20 World Cup.

The competition Rongen's squad will face in South America will be a litmus test for this country's player development system. The U.S. Soccer Federation's Development Academy has just completed its fourth season, and while it's still too early to see an effect at the senior level, the performance of the U-20s will provide an interesting gauge of the program's overall progress. The U.S. team figures to rely more on full-time professionals than it did two years ago, when the side was eliminated in the group stage. No doubt, Rongen & Co. will be looking to beat that mark and go deep into the tournament.

3. The Women's World Cup and its impact

The international calendar, which forces the Women's World Cup and the Olympics to be held in consecutive years, certainly does the women's game no favors. But once again the U.S. women's national team will be hoping to bring some badly needed attention to its sport, as well as bring home the World Cup trophy for the first time since the magical summer of 1999.

The tournament will include the usual contenders, such as reigning champion Germany as well as Brazil and Japan. But before the U.S. can worry about any of them, the Stars and Stripes will have to navigate a tricky group with Colombia, North Korea and Sweden, the last two of which are ranked in the top six.

Will claiming the World Cup title be enough to save the ailing WPS? Given that the league was started in 2009 in the wake of the U.S. team's gold-medal triumph at the 2008 Olympics, that's debatable. But after losing four teams in the past year, WPS will take any boost it can get.

2. Bob Bradley's rebuilding job

This is the time in the World Cup cycle when Bradley is staring at one of those 1,000-piece jigsaw puzzles, as each aspect of his team has questions to be answered.

Some key performers in defense, such as Carlos Bocanegra and Steve Cherundolo, are getting up there in age and need to be replaced. The troublesome left back spot remains, well, troublesome. Can young upstarts Tim Ream and Omar Gonzalez make it a seamless transition?

Up top, the jury is still out as to whether Charlie Davies will fully recover from injuries sustained in a car accident 14 months ago. Jozy Altidore is still riding the pine in Spain, yet remains first on the forward depth chart for the national team. Youngster Juan Agudelo impressed during his international debut, against South Africa in a friendly in November, but at just 17 years of age, he has a lot of growing to do before he can be counted on to deliver consistently.

Even midfield, the presumed strength of the team going forward, looks a bit uncertain. Will new arrival Jermaine Jones survive being banished to the reserves of club side Schalke and make a strong case for playing for Bradley? And given Stuart Holden's sparkling season at Bolton, what is his role going forward? Could he be inserted into the central role that he plays at the club level, and how would that affect Michael Bradley?

These are just a few of the questions the U.S. manager will need to sort out in 2011.

1. The Gold Cup

It might not have the cache of the European championships or Copa America, but the quest to be king of CONCACAF remains a crucial part of the U.S. World Cup cycle.

When Benny Feilhaber sunk Mexico with that wondrous volley back in the 2007 final, it set in motion a series of steps that allowed the U.S. team to move forward. The win clinched qualification to the Confederations Cup, which then allowed the team to acquire a vital amount of experience and confidence heading into the World Cup in South Africa.

The same prizes will be at stake this summer, with the Gold Cup final set to take place at the Rose Bowl in Pasadena, Calif. With a win, the U.S. team's path to Brazil will be laid out. Defeat, however, will rob the squad of some special opportunities to progress and put Bradley under considerable pressure.

Jeff Carlisle covers MLS and the U.S. national team for ESPN.com. He is also the author of "Soccer's Most Wanted II: The Top 10 Book of More Glorious Goals, Superb Saves and Fantastic Free-Kicks." He can be reached at eljefe1@yahoo.com.