Some coaches will allow it while others don't. What I'm talking about is injured players; some coaches will let their players play if they want to while other feel liable if they get hurt even worse. It's up to you as a coach, but in my opinion if you have a player that's injured, I wouldn't play them incase the get hurt again and are out even longer.
However, if a coach allows you to play, you need to consult a doctor first and make sure it's alright. Some injuries you may be able to play with, well depending on what sport you play, while others you just need to rest so they'll heal. It may be hard just sitting there watching you teammates play and have fun, but you just need to be patient. One major question that a lot of doctors and coaches get is indoor volleyball safe during pregnancy? Well it all depends, some doctors will tell you a straight up no while others say its fine if you've played volleyball all your life. However, my opinion on this on is no matter, I wouldn't play volleyball if I was carrying a baby in my stomach. I would be too afraid of something happening to it and it would be my entire fault and it would just make me feel terrible.
Some rules for indoor volleyball won't let players play with injuries, but others do. And that goes the same is indoor volleyball safe during pregnancy, some leagues will just flat out tell you that you can't play. However, if you do get to play while being pregnant, it may be hard finding volleyball uniforms for sale that will fit you!