With less than six months remaining on his contract at the Emirates Stadium, Sanchez is expected to leave the club before the January transfer window closes with United in pole position to sign the Chile international.
The saga over the player's future has developed quickly over the past week. The 29-year-old was widely expected to join Manchester City this month but the Premier League leaders subsequently dropped their interest; unwilling to meet both Arsenal's and the player's financial demands.
United are now in talks over a deal that could see Henrikh Mkhitaryan move to the Gunners in a straight swap deal – one of two proposals on the table with the club also ready to pay an outright £35m fee.
Tensions between Sanchez and the rest of the Arsenal squad have been simmering for some time. The former Barcelona and Udinese star was involved in a confrontation with Laurent Koscielny at the club's training facilities as far back as last March.
In November, a reported a bust-up in the aftermath of a win against Burnley saw members of the squad call Sanchez out on what they perceived to be his bad attitude. Signs of that division were there when Arsenal and Palace met at Selhurst Park on 27 December. Sanchez scored twice in a 3-2 win that evening – but a number of his teammates, including Koscielny, Hector Bellerin and Jack Wilshere chose not celebrate his first goal.
With the relationship between the squad and Sanchez already poor, the Evening Standard now report the rest of the Arsenal dressing room is now weary of the ongoing saga and want to draw a line under it before they return to Premier League action against Palace at The Emirates.
Sanchez was dropped for Arsenal's last top flight contest – a 2-1 defeat to Bournemouth last Sunday [14 January] with Arsene Wenger explaining post-match a move was imminent.