The Chile global entered the final six months of his Arsenal contract at the start of January and had been expected to move to City, with Sanchez said to be keen to join up with Pep Guardiola once again.
Jose Mourinho labelled him a "phenomenal player" at his press conference later that day but both the United boss and Manchester City manager Pep Guardiola were tight-lipped about a potential move for the forward.
"His situation is not decided one way or the other so I left him at home", he said. "You want to focus on the players who are on the pitch who can do well for the club".
And Cole believes that Mourinho needs to take advantage of this window of opportunity to sign Sanchez this month.
Wenger admitted on Friday that Sanchez would not be signing a new deal, paving the way for him to leave the club in the current transfer window, adding that a bidding war could help Arsenal.
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As reported by ESPN on Sep.
"I look at Arsenal without Sanchez and Ozil and I'd ask what name would fans get on their shirts if those two go?"
"They have to accept this responsibility and it can't happen again because these players should be tied down to long-term contracts, they shouldn't be going to enhance United or City".
"I honestly believe Mkhitaryan is one of the best players in the Premier League, his confidence is just shot at United".
"My understanding from the blue side of Manchester is that they don't want to pay anything like £35m for Alexis Sanchez, they would be more happy to pay £20m".