Valentine Holmes tried it. Jarryd Hayne actually made it.
But no recent player has ever done the reverse and gone from the NFL to rugby league and made a name for himself.
Not since 1977, anyway.
The passing of former Newtown Jets player Manfred Moore filtered through to Australian shores with only long-time league followers familiar with the name.
Moore, a former Oakland Raiders player who also enjoyed stints at Tampa Bay, Minnesota and San Francisco throughout his NFL career, made the bold move to test his hand at rugby league just 98 days after the Raiders won Super Bowl XI.
Newtown were coming off a dire 1976 season where they won just three games to finish with the wooden spoon.
"So then 1977 there was a big hype around the game that an NFL player was going to try his hand," Jets ground announcer John Lynch told NRL.com.
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"There was only one other bloke [Alvin Kirkland] who played for Parramatta but that was in the 50s.
"Manfred's arrival was in the papers and the competition was pumped for it. We got our highest crowd of the year, he turned up in a red sports car, it was like a rock-star opening."
Respected sports journalist, historian and author Ian Heads painted this picture when describing Moore's stint at the Jets.
"He was no superstar but he added something to the competition as a pioneer in his own way - and his story is a good one, of a 'stranger in a strange land' and about a bloke coming from far away to have a crack at a new and fierce game that even Manfred soon came to discover was tougher than he could have even imagined," Heads said.
"In his stay, he added something different to the Sydney newspaper copy."
Moore scored a try on debut against Western Suburbs with one of his first touches to bring the crowd to their feet, but his overall experience proved rugby league was a difficult sport to adapt to on the run.
"He was very keen and eager and if you were running at him he'd knock you over," Lynch said.
"But if you sidestepped he had little idea. It was a gimmick thing where he did fail at certain aspects of the game but it would've been a big thing for him to come out to a foreign country and with limited access to family.
"He was very friendly and nice to everyone who met him. He had a tall basketball look about him."
The club's media officer, Glen Dwyer, recalled Moore's brief stint in the game.
"What a brave effort it was for a fella to come out on his own, travelling thousands of kilometres and play a game he'd never seen before," Dwyer said.
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"He had seen rugby union on the television but didn't know there was a difference.
"It gave him an idea that he couldn't throw the ball forward. When you take that into the account that he was thrown into a cauldron playing for a team that was at the bottom of the table in the highest standard competition in the world, he made a decent fist of it.
"Ian Heads points this out that players going in the other direction to the NFL hasn't been easy.
"No one has ever claimed a permanent spot and in Manfred's case he was a rare one who attempted the switch and proves it's just as hard the other way."
Moore's final visit to Australia came in 2007 at a 30-year reunion organised through John Singleton, who originally brought the American to Newtown three decades earlier.
"It was a very successful and blissful return for him," Dwyer said.
"He also came to a game at Henson Park and met up with a few of his old teammates and got some photos with them.
"I said it to him at the time that his willingness to give rugby league was to be greatly admired but he said he wasn't looking for that, he wanted to leave the game in a better place than what it was when he arrived."