On Friday the U.S. men's national team kicks off qualifying for the 2018 World Cup in Russia. And while the team's first opponents -- St. Vincent and the Grenadines and Trinidad & Tobago -- don't exactly strike fear in the hearts of most U.S. fans, these matches will be important for Jurgen Klinsmann & Co. after a string of disappointing defeats that's generated questions about the U.S. player pool and, in particular, which young players will step up this cycle.