Basel dropped 3 at the back lately, they've been playing 4-2-3-1. So I guess it's less likely we'll feature 3 at the back, unless Mourinho wants a really quiet controlling game. Without both Pogba and Matić, as you suggest, it might be the only way to get it.
We have several options to choose from for this game that anything is possible. Won't be surprised if Mourinho gives Pogba the first 45 minutes to give him full fitness then sub him during HT.