players and they were replaced by someone that didn't make the team, that would be like taking a starting QB and have a walk-on takes his place. Even if they don't play, that means someone on the bench is now playing that probably wasn't as good as the travel player that left.

In Volleyball, there's only 6 players on the court. It's not that hard to target the worst player to get points. You can try to hide them, but sometimes it's better to play with 5 than just having another body out there. If you can't pass the ball to the setter, you can't win. If you take that 6' middle blocker off the court and replace her with a 5'8" player that was sitting on the bench, you're losing a huge amount of offense and blocking.