The Chile international is out of contract at the end of the season and is free to sign a pre-contract agreement with overseas clubs.
Manchester City lead the race for the Chilean and know that they can sign him for free at the end of the season. City had offered Sanchez a signing-on fee of around £25m to let his Arsenal deal run out and move to the Etihad in the summer of 2018.
However, Pep Guardiola wants Sanchez in January after Gabriel Jesus was ruled out for two months and Sanchez is prepared to waive his signing-on fee to seal his move to the Etihad in the next three weeks.
City are upped their interest in Sanchez in the last fortnight and believe they can seal a deal for the Chilean in the next week or so.
Arsene Wenger had been willing to let Sanchez run his contract down as a matter of principle but senior members of Wenger’s squad have urged the Frenchman to sell the Chilean so that the Gunners can concentrate on the remainder of the season.
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Sanchez’s attitude since Arsenal blocked his move to City on deadline day has irked a number of members in the Arsenal squad and the forward recently clashed with his team-mates after a draw with Southampton in December.
City face Liverpool at Anfield on Sunday and would need to register the former Barcelona man on Friday for him to participate against Jurgen Klopp’s men.