Centre-backs
Chris Smalling
He continued being frozen out of the England setup and that comes as little surprise. Mourinho likes consistency in his central defenders and has selected Smalling on a regular basis. At the moment, he has limited options and will most likely stick with his pairing. Smalling did not take part in the UEFA Nations League with England and should be fresh. Out of all the United centre-backs, he looks like the most assured.
Against Palace, it is the general expectation that he will face a less lethal offensive force when compared with City's. His 6 ft 4 frame will be an advantage when dealing with aerial balls and defending set pieces. He can also cause problems on the other end.
Victor Lindelof/Marcos Rojo
Given that United have struggled defensively, Mourinho may give Rojo his first start of the season. Ideally, he will be the left-sided centre back. He has slowly been eased into training in the last couple of weeks. Palace would be an ideal test to give Rojo a chance to state his case. Already, Phil Jones and Eric Bailly have shown to be error-prone and Rojo could be that assurance that United need in that position.
On the other hand, Mourinho may opt to stick with Victor Lindelof, who has really stepped up from the fringe player he was last season. He has been trusted with the obligation of taming offensive players against Chelsea, Juventus and City so he too is a top candidate to start. On a good day, Lindelof can be ruthless and worth every penny that United paid for his services.