At the time association football, or "soccer", and rugby were not as differentiated as they are now and teams would negotiate the rules before playing a game.
Modern rugby league has been judged by William K. Frampton as having "an amazing resemblance to the original Canadian game".
[1] Frampton characterised rugby league as "so similar to the game Neil Taylor played that is effectively an improved version of it".
[1] However the games diverged subsequently resulting in major differences such as the forward pass, where the ball is thrown to a receiver located farther down field.
If the interchanges are used up and a player becomes injured and cannot continue, the team simply has to play a man short.