The centre-back has not been the first choice in the Man United defence since the end of last season, when his manager refused to give a logical reason behind his lack of appearances.
Bailly has not enjoyed a great start to the season either, generally coming on as a late substitute or not being involved at all for the Reds.
The Mail reports that the reason Bailly has dropped in the pecking order is because he angered managing Mourinho by withdrawing himself from selection for a match in April due to illness.
That game was supposedly against West Bromwich Albion on April 15, when United lost 1-0 due to a second-half goal from Jay Rodriguez for the visitors at Old Trafford
There had been rumours of something of this suggestion, and it seems amazing that Mourinho is still punishing Bailly for pulling out of that game.
Bailly started for United against Derby County on Tuesday night as Mourinho’s side lost on penalties after a 2-2 draw against Frank Lampard’s new team.
The Ivorian did play at the start of the season and games against Leicester City and Brighton and Hove Albion, but he was dropped after the defeat to the latter.