Fighting commissions will not allow that to happen anymore. Fighters safety comes first. In the past if a fighter is unable to move on to the next bout there was a replacement. That does not make sense for an alternate to bypass the first 2 bouts and go straight to the final match which has happened in several times in ufc tournaments, where the fresher alternate won it all.
That delitigtimizes fighters toughness by having alternates "not "fight their way to the finals.