The Englishman, who enjoyed his best ever campaign under Louis van Gaal last season, has quickly descended into obscurity at Old Trafford, managing just 13 Premier League starts since August.
His most recent display, away to Southampton, was once again hallmarked by shakiness and a highly critical reception from supporters.
And according to the Telegraph‘s James Ducker, Mourinho will listen to offers for the 27-year-old in light of the reportedly imminent arrival of Burnley’s Michael Keane.
Smalling has enjoyed some fantastic moments at Old Trafford: has was, once upon a time, the man who ascended from non-league football to the very heart of Man United’s back four. There were times last season where he was simply unassailable.
But football is a game of rapid evolutions and, one year on, Smalling cuts an incongruous figure in this current United side – a symbol of the past three seasons: occasionally promising, regularly substandard, and ultimately not good enough for a manager who won’t tolerate any signs of deadwood next season.
The idea of an ‘overhaul’ has been a prevalent and indeed frequently spouted term since David Moyes brought the entire side down to a status of gloomy mediocrity back in 2013, and it still applies now. Smalling can do a job, of course, but he is something of a grim reminder of the past. But with Keane set to return over the summer, you sense that Mourinho is hellbent on looking forward, and not back.