#3 Chris Smalling
One of the longest-serving United players, this is Smalling's eighth season at Old Trafford. All these years, Smalling could never establish himself as a first choice centre-back at Manchester United. He has never made more than 25 Premier League appearances in a season, except for 2015/16.
His performances have not been great over the years and this season is no exception. Smalling has been quite poor and indecisive. His passing wasn't great either and some of his markings were very poor. Manchester United lost 3 games in Premier League this season and all of them had Smalling at the heart of United's defence.
In his 13 PL starts, Manchester United were able to keep only 5 clean sheets and conceded 12 goals. United have depth at the back and when everyone is fit, Chris Smalling will be Jose Mourinho's fourth choice centre-back.