- or can I show up to games with "just" 45 active?

Nothing to stop you having less than 46 active players, I've had to do it a few times due to injuries.
I guess it might make the active players a bit more more susceptible to injury if there's less depth but I'm not sure.

Maybe it has changed but last time I decided to mess with it the sim engine force activates 45 players. Therefore, if you're in preseason action and want to guard everyone it'll flip your inactive to active randomly to get to the 45 count.

Yeah that's the situation for me.

I have 8 players with an injury designation and a few who are barely over their previous injuries.

I was hoping I could just line up 45, instead of having to use IR for some of the worse cases. It's not like there's any decent replacements in the FA pool anyways.

It will allow 45 active players, any less and the AI will redo your depth chart.