Pacheco (shoulder) won't practice Thursday, Matt McMullen of the Chiefs' official site reports.
Pacheco didn't practice Wednesday, either, so what the running back is able to do during Friday's practice -- if anything -- will loom large with regard to his chances of playing Sunday against the Bills. If Pacheco is sidelined this weekend, Jerick McKinnon (groin) and Clyde Edwards-Helaire would likely split work out of the backfield.