Does anyone know why/how/when this rule came into effect in the NFL? I am curious to know the logic behind having a 53-man roster, but then not allowing all of them to play in the game itself. Is it a salary cap related mandate that began in the 90s, or was it like this in the 70s & 80s? I wonder if 46 active players cost the teams substantially less money.
The league changed the number from 45 to 46 when they negotiated the new CBA in 2011 that goes through 2020. So it's possible that a future CBA could get rid of it altogether to go from 46 all the way to 53. I hope it happens sooner than 2020 given that it doesn't make any sense for organizations to go through the trouble of acquiring, coaching & paying all of the players but not playing them!
Given the way injuries affect each roster, and the long-term player healthy-safety concerns, it would make sense to increase roster sizes which would allow marginally injured players more rest to recover before being brought back onto the field. It could also help to reduce snaps for specific -- high-risk -- players in certain game situations.
It would also be a well-earned benefit for draft & player development oriented teams like the 49ers because they would be rewarded for having better players at the bottom of the roster in spots 47-53.