We always try to have a full 8-man bracket. If a placer from a sub gets hurt or chooses not to compete, we will fill the spot with the next in line from his (or her) own sub. In cases where that is not possible, we will pull one from the other sub. With almost certainty ... if we need a wrestler ... we will call them. The odds of showing up at District, having not earned a spot, and getting to wrestle, would be extremely rare.
Hope this answers your question! Unfortunately, time does not allow us to make a great number of Saturday morning changes!