Mourinho discussed Pogba's 'poor' form in a press conference the other day. He's also talked a lot about midfield positions, further fuelling the debate.
The whole situation is iffy, for me. Sanchez comes in, Pogba (having been our best outfield player all season) is dragged off, dropped in the Premier League and subsequently dropped in our biggest game of the season.
I think it's drama for drama's sake and it's just a bit boring. Shaw, Martial, Mkhitaryan, Pogba... It seems there's always a problem with talented players in the squad who could otherwise be on the pitch and doing well.