Manchester United will not sign Alexis Sanchez unless Henrikh Mkhitaryan agrees to move to Arsenal, according to the Armenian's agent Mino Raiola.
Mkhitaryan was left out of the squad to face Stoke on Monday night with Jose Mourinho admitting there are doubts about his future.
He has been linked with a move to Arsenal with Sanchez moving the other way.
Raiola has said Mkhitaryan could move to Arsenal, just 18 months after arriving at Old Trafford from Borussia Dortmund for £26 million.
Raiola said: "Manchester United is not going to sign Sanchez unless Mkhi agrees to join Arsenal.
"Mkhi has not decided yet.
"Mkhi is going to do what is best for him. He has two-and-a-half years left on his contract, so it's his decision.
"Sanchez is part of the Mkhi deal, not the other way around."
Mkhitaryan has scored 13 goals in 63 appearances since moving to England from the Bundesliga but has only started two of United's last 16 games.
Following the 3-0 win over Stoke on Monday night, Mourinho accepted he could leave this month.
He said: "I didn't select him today because I wanted players fully focused and I understand that with so much talk and speculation it is not easy for Mkhitaryan to play... so I prefer to protect him and the situation.
"If he stays here he is a very good player that this season started very, very well and come a little bit down but last season did he amazing things for us, helped us to win the Europa League, being one of the most important players."