CHULA VISTA, Calif. — A few weeks before USA Football went off to defend its world championship title in Düsseldorf, Germany, the team's most recognizable player and top star wasn't the first one on the field. In fact, on this sunny and crisp morning in Southern California, Darrell "Housh" Doucette was one of the last players to begin warm-ups. But Doucette still commanded the attention of his USA Football teammates. Donning tinted visor shades with a navy-blue USA headband pressed over his braided head, Doucette leaned in to share a few words of wisdom with a teammate as they began to stretch...