Playoffs is 1-8, with 9-12 still available as replacements. Higher you're ranked the faster you're called back into the tournament. On top of that additional fighters (13-14) will be brought in as even further precautions.
As for the regular season, all PFL needs is 8 fighters at the end so it doesn't matter if there's injuries. Those fighters just lose their opportunity at gaining points and everything goes on accordingly.
Having said that, PFL has added some safety nets regardless. For example the August 30 show was added to give any injured fighters a second chance to gain points. I'm also speculating, but PFL must have added something into these fighters contracts saying opponent are scheduled to change, cause they've been switching out opponents or mixing and matching cards at the last second with zero resistance from the fighters.
