A nasty challenge from David Luiz, which ought to have yielded a red card, left the Belgian with a nasty gash on his lower thigh, forcing Jose Mourinho into replacing the Belgian at half time.
Initial impressions of the knock appeared to reveal no more than a nasty contact injury, but he exact severity of the injury will only be known after Fellaini has a scan.
Various reports, however, have suggested that the Belgian could be absent for several weeks.
It is unlikely that, with Man City’s win at Old Trafford back in September still fresh in Mourinho’s mind, Fellaini would have featured against Pep Guardiola’s side on Wednesday anyway.
City’s win was characterised by their ability to exploit the midfield duo of Fellaini and Pogba, with Kevin de Bruyne (a doubt for Wednesday), Raheem Sterling and Nolito all frequently taking advantage of the home side’s complete lack of defensive cover in midfield.
One suspects that Mourinho, especially after suffering his worst defeat as a manager since 2010 at his former, will want to consolidate his midfield with a more defensively oriented midfielder alongside Pogba.
With this in mind it seems as if Michael Carrick, an instrumental component in Man United’s 4-1 win over Fenerbahce last week, will most likely take the Belgian’s place.