Fun fact that many don't know. There is actually a 90 player limit for NFL teams. This includes the main roster, practice squad, and any player on reserve lists. The 49ers are 2 or 3 players away from reaching that maximum (I don't know if Brandon Aiyuk counts or not)
The 49ers now are leaning toward not placing DE Nick Bosa on injured reserve in part because they’re running out of injured reserve spaces, per source.