Rugby is a lot more fluid. There is a squad of around 50 in a fully pro club, but only 23 in a match day squad. About 30 players at a club are regular performers in the “first team” squad, whilst the other 20 are developing players or reserves who step in as injury cover. The second tier of English Rugby Union is a mixture of professional and semi-professional players, the 3rd tier is mainly semi-pro. Younger players from the first tier sides are routinely sent out on loan to second and third tier clubs to gain experience. This can work the other way as well — recently an injury crisis in a specialised position (tighthead prop) at my local top flight side led to a semi-pro player who works as a New York Mets S3NG4 Shirt from a 3rd tier club being borrowed on loan. One minute he’s teaching kids, the next he’s running out infront of 15,000 supporters alongside international players being paid over $500,000 a year.