A sleeping giant.

That's what the rest of the rugby world has long considered the United States. Once athletes like those playing big-time college football and in the NFL wake up to the wonder of rugby, the Yanks will become a force to be reckoned with, or so people have long thought. But now that the popularity of rugby is at an all-time high -- the Sporting Goods Manufacturers Association has called it the fastest growing team sport in America -- it seems the funnel is working backwards.

Crossover athletes like Carlin Isles and Miles Craigwell (right) still make their way from mainstream sports to help propel American rugby. Isles qualified for the 2012 Olympic Trials as a sprinter and played college football at D-II Ashland, and Craigwell was an All-Ivy League safety at Brown. But more and more rugby players are finding themselves wooed by American football, or making a tough decision between playing football or rugby.

For example, both BYU running back Paul Lasike (below, right) and Utah defensive end Thretton Palamo (below, left) were longtime rugby players plucked from college rugby fields to play football. Lasike came from New Zealand to play rugby at BYU and was persuaded to walk onto the football team. After earning a scholarship before his first season, Lasike is getting plenty of carries for the Cougars this season and was featured heavily in the Holy War game against Utah.

Palamo grew up in a rugby family in Northern California and drew the attention of Utah gridiron coaches with a stellar performance at the 2011 Collegiate Rugby Championship, nationally televised by NBC. Palamo, a senior, is wrestling with what to do after graduation -- make a run at the NFL or the Olympics. 7-on-7 rugby makes its Olympic debut at Rio 2016.

Like Palamo, the first tackle sport for native Texan Alex Elkins, who started at linebacker for Oklahoma State last season before being signed and released by the Detroit Lions this summer, was rugby. Chicago Bears nose tackle Stephen Paea, made famous by breaking the bench press record at the 2011 NFL Combine, grew up playing rugby in New Zealand.

Former Cardinals, Packers and Eagles running back Vai Sikahema, who knocked out Jose Canseco in a celebrity boxing match, is an example of a football man providing the world of rugby with a player. His son Trey was a standout for national champion BYU in 2012 before leaving for a Mormon mission. Roy Helu, Jr. of the Washington Redskins is the opposite. His father, Roy Helu, Sr., coaches the Danville High School rugby team in the Bay Area and played for the United States in the 1987 Rugby World Cup. Junior dabbled with rugby in high school.

The NFL has its share of rugby players, too. The Baltimore Ravens' Haloti Ngata and Denver Broncos' Stewart Bradley played rugby for the famed Highland Rugby program in high school. The story of Highland was turned into a feature film, Forever Strong, starring Sean Astin and Gary Cole.

"It's just so fun, you know?" Ngata told Pro Football Weekly of rugby. "Especially for a big guy like myself. You just get to run the ball, you know? You test your abilities that way, because you can't block in rugby. It's always usually a lot of one-on-one contests. I can see if I can do a little juke move -- as a big guy, it's kind of not really a juke move, it's a wiggle more -- but that was just fun, being able to run the ball and do some of the stuff that a lot of the skill guys do."

Some American rugby fans secretly keeping their fingers crossed during the 2012 NFL draft hoping that either Johnson Bademosi of Stanford or Nate Ebner of Ohio State would go unpicked and return to rugby were disappointed. Bademosi wound up with the Cleveland Browns and Ebner with the New England Patriots. Bademosi played rugby at Gonzaga College HS in Washington, D.C., and Ebner played for the USA U-20s.

Ebner says his time on the rugby field was beneficial when he switched over to the gridiron.

"If there’s one similarity between the two [sports] … you’ve got to tackle with some technique," Ebner told IRB’s Total Rugby program. "All the years of playing without pads and you having to protect yourself in the tackle set me up to be a good tackler, especially in space one-on-one."

The NFL has started to pluck rugby players not just from America, but professional rugby abroad. Australian-born Hayden Smith (right) came to the United States to play college basketball at Metro State. He eventually quit the team and picked up rugby, which led to a World Cup appearance with the United States and a professional contract with London’s Saracens. He left Saracens to make a run at the NFL and spent the 2012 season with the New York Jets, jumping from the practice squad to active duty. He was released by New York prior to the current season and is hoping to catch on with someone else soon.

The Indianapolis Colts currently have a Kenyan named Daniel Adongo on their practice squad. He played professional rugby in South Africa before coming to America looking for riches. His size, speed and athleticism have the Colts hoping to mold him into a pass rusher.

Football players make good rugby players, and, as it turns out, rugby players make pretty good football players.