The former Arsenal star is reportedly eyeing a move away from Old Trafford and is now a doubt for Tuesday's clash with Juventus.
Alexis Sanchez
Alexis Sanchez was absent from Manchester United training on Monday amid reports that he wants to leave the club.
The Times claimed over the weekend that Alexis is unhappy with Jose Mourinho and that his agent is on standby to talk to interested clubs should they come calling in January or next summer.
Alexis was absent from the session ahead of Tuesday's Champions League clash with Juventus, throwing his participation in the game into doubt.
The Chile international has struggled for form thus far this season, scoring a single goal in seven Premier League appearances.
He has played 90 minutes just once this season, in the 2-1 win over Leicester City on the opening day, while he featured for just five minutes in Saturday's 2-2 draw with Chelsea.
After being signed from Arsenal in January 2018 in a swap deal that saw Henrikh Mkhitaryan join the Gunners, Alexis has made 26 appearances for the Red Devils.
He has scored just four goals and provided six assists in that time, with Mourinho using him sparingly.
Alexis was left out of the squad to face West Ham earlier this season, and has been substituted numerous times.
Jesse Lingard, Diogo Dalot and Marouane Fellaini were also absent from the session, as the club prepares for the biggest game in their Champions League campaign thus far.
United have so far played Valencia and Young Boys in Europe, and sit second behind the Bianconceri, having drawn with the Spanish side and beaten the Swiss outfit.
Of course, the match with Juventus offers the chance for United to renew acquaintances with the iconic Cristiano Ronaldo, who has been enjoying life at his new club since a stunning move from Real Madrid.
Ronaldo has thus far scored five goals and registered five assists in nine Serie A games.