Since its inception in 1996, MLS has played a major role in funneling little-known players into the U.S. national team's player pool. Just take a look at the Yanks' roster for last month's World Cup qualifying loss in Honduras. Of the 24 players selected by coach Jurgen Klinsmann, 18 play (or used to play) in MLS.

MLS is rarely more important to the national squad's fortunes than in the year before a World Cup. For the league's most promising Americans, the final Hexagonal round of qualifying has historically been a proving ground of sorts, even if success doesn't necessarily translate into a trip to the main event.

In 2005 and 2009, the World Cup berth-clinching goals were scored by Steve Ralston and Connor Casey, respectively. Neither player was rewarded with a trip to the world's biggest sporting event the following summer. Others, such as Stuart Holden, who earned his first U.S. cap less than a year before South Africa 2010, came out of nowhere and stuck.

This year will be no different. A number of MLS stars have already firmly established themselves in Klinsmann's plans, and there's plenty of time for others to do the same. It's already clear that players like Matt Besler, Omar Gonzalez and Graham Zusi -- and perhaps Landon Donovan -- are going to play a major role on the road to Brazil.

Barring a severe drop in performance, one wouldn't expect those players to lose their status this year as U.S. regulars. It can happen -- see Brek Shea in 2012 -- but for the most part, another year as an MVP finalist isn't going to help Zusi move up the depth chart as much as a terrible season would drop him down it.

But for a few others, how they fare with their domestic clubs this season will determine their chances of sticking with the U.S. over the long haul. With the 18th MLS season set to kick off Saturday, here are five on-the-bubble Yanks who can play their way into consideration for a spot at the 2014 World Cup.