Past NFL players’s inferior conditioning were already exposed when taking part in other sports like pro wrestling (most memorably Kevin Greene for me; Bill Goldberg also struggled a bit before he completely re-trained his body) & ABC’s ‘Superstars’ athletic competitions (except for Jason Sehorn, the other half-dozen…

Nah, NFL players don’t have the physical endurance for sevens rugby. Even 15-a-side pros won’t necessarily thrive. But I do think gridiron players can do well in rugby league; unfortunately the current generation can’t tackle well.