Jose Mourinho admits there are 'some players in the football world' that a club like Manchester United must try and sign if available, with Alexis Sanchez amongst them.
The Chilean forward is out of contract at Arsenal this summer and is being widely linked with a move away from the Gunners during this month's transfer window.
Manchester City is believed to be the preferred destination for Sanchez, though the Premier League leaders are said to be unwilling to pay more than £20m for a player that will be a free agent in the summer. Arsenal are holding out for closer to £35m for their player.
Manchester United are looking on with interest from the sidelines and, while not keen to talk about Arsene Wenger's player, Mourinho admits the Red Devils have a duty to be on top of the situation if Sanchez is to become available.
"I don't think it's correct to say things about Alexis Sanchez," the Portuguese said.
"At the general level, what I can say is that myself and the Manchester United board, we don't believe a lot in the January market. We don't believe in signing players just to sign a player, just to do something. We don't believe in that.
"What we believe really is that there are some players in the football world, if you have a chance to sign them, it doesn't matter if it is in January, March or July, you have to try.
"But in relation to Alexis Sanchez, I don't say a word. The only word I can say is the same word that everybody says, he's a phenomenal player.
"Apart from that, (he's an) Arsenal player, I feel I shouldn't say much more than this."
Man United are 2/9 to beat Stoke on Monday night at Old Trafford. The Potters are 14/1 while the draw is 6/1.
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