Herrera, Fellaini, and Pogba in midfield is pretty much a certainty. Valencia, Darmian, and Blind will also play for sure. The front three will probably be Mkhitaryan, Rashford and Martial. Bench houses Carrick, Mata, Lingard, and Rooney which makes things look a bit stronger in terms of options to change the game. The rest is basically a case of who is fit enough. I am hoping Smalling or Jones make it back a bit sooner as their estimated return dates were around the Arsenal game I believe. Maybe Bailly will actually be OK if he just rests up rather than trains? Otherwise, it's Darmian at CB and Young at LB.
de Gea
Valencia Darmian Blind Young
Herrera Fellaini Pogba
Mkhitaryan Rashford Martial
---
Romero; Tuanzebe; McTominay, Carrick, Mata, Lingard; Rooney
If we are still this depleted then I think coming away with a 2-1 defeat is not a bad result, as long as that's the worst case scenario. I think we'd still nick the tie over two legs with that, provided we get a couple of players back from injury and nobody else takes a knock.