IMO, retirements, and FAR 117 (we are one of the few carriers to operate both pax and cargo airplanes) implementation. So, how the company implements the so-called "Cargo cut-out" will determine how many additional bodies we need to operate the 6 or so pax airplanes with pax rest rules vs cargo rest rules.
Personally, my body doesn't know the difference when I fly cargo vs pax...I'm tired when I am tired!! (Just amazing how politicians think, but that is a different discussion)