modern leagues pitchers injuries

In 2023/2024 leagues, there seems to be more injuries or possible SP injuries than in ATG, where it's really not an issue...I don't think I've had any SP have to sit out a game (maybe once only) in almost 40 leagues there

my question is this, in ATG (or maybe all 365), if you only have 2 catchers on roster and one is injured, I believe HAL makes it impossible for the next catcher (only one left) to get injured....meaning, if he hits an injury on his card, HAL would disregard it and leave him in the game....if that's not correct, somebody set me straight please

so, here's the question....2023/2024 leagues and maybe all 2000+ leagues (not sure) require a 5 man SP rotation.....but some pitchers have 2, 3, or worse injury ratings....if, a team only has 5 players capable of being an SP, and one gets injured, what happens ?....does HAL use an RP to start any game, or does he go with a 4 man rotation until the injured other starter returns, or does the player not get injured like the catchers in ATG ?...or something else...

thanks for any feedback

A relief pitcher is used.

This just happened to me in an ATG league. My only R4 (and also my worst pitcher) got the call for three starts. Not surprisingly he went 0-3 and it wasn't pretty!