The 36-year-old former Sweden global suffered a horrific knee injury back in April 2017 in Manchester United's Europa League campaign and despite making an early comeback, he is yet to reach full fitness.
The Red Devils are believed by some media outlets to be in pole position to land Arsenal forward Sanchez after agreeing to meet the Gunners' £35 million asking price - a move which has forced Manchester City to drop their interest in the Chilean star unless they can now land him on a free transfer in the summer.
And Mourinho concedes that the 28-year-old could leave Old Trafford if they receive an acceptable offer.More news: 6 senators say they've reached immigration deal
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Asked about Mkhitaryan's future in Manchester, Mourinho - speaking ahead of Monday's visit of Stoke City - said: "My approach is that every player has a price".
Mourinho admits winter is not a time in which he usually likes to do any business, unless circumstances dictate that purchases are necessary or a top player becomes available. I think every player has a price. Blind in the sense that this player is untouchable, this player can never be sold.
Jose Mourinho has outlined both his, and the clubs transfer policy with regard to making signings in the January transfer window. But I like my squad, I like my players; the more time I spend with them, the more I like them.
"Normally, next summer, we would try again to improve our squad in the different departments, to try to make every department stronger". But Mkhitaryan played the last match in the FA Cup and probably will play the next one [against Stoke]. Then it's up to us to make the decision: yes or no. "So Saturday [he is] training, then Sunday [he is] selected and Monday [he will] play".