Sanchez has consistently refused to sign a new contract with the Gunners and is on course to become a free agent at the end of the season. This month is therefore the last opportunity the club will have to command any kind of transfer fee for him.
According to BBC Sport, Arsenal officials 'privately accepted' a number of weeks ago that the Chilean superstar is 'likely' to be leaving before the end of January.
As such, it is said that he will be sold in the event of a 'suitable' offer - what is considered 'suitable' is still somewhat vague - and a replacement can be sourced.
Sanchez has been heavily linked with Manchester City, indeed almost joining the club for £60m last summer, and the BBC notes that the Premier League leaders would be his preferred destination. But there has been sudden late interest from Manchester United as well.
As reported by others, Alexis Sanchez will leave Arsenal this month if suitable offer made + replacement secured. Hierarchy accept/expect it, conversations continue with Man City. #AFC wanted £35m, #MCFC £20m, possible compromise £25-30m. 1st choice replacement Bordeaux’s Malcom pic.twitter.com/lZtS98ocqk— David Ornstein (@bbcsport_david) January 11, 2018
A report from the Guardian claims that United have made an offer of £25m, trumping the earlier £20m offer from the Etihad Stadium as well as offering Sanchez better terms than City. Other rumours suggest Henrikh Mkhitaryan could be included as some form of part-exchange.
The newspaper explains that Sanchez has already agreed personal terms with City, but that Arsenal are yet to respond to the £20m offer. The BBC report corroborates that, stating there is currently 'no agreement' on a fee.
The Independent state that Sanchez 'has his heart set on City', which is the biggest hurdle for United. Even if Arsenal initially reject the proposal from City and are more willing to do business with United at the higher price, the player also has to accept the deal.
If he really is that desperate to reunite with former Barcelona coach Pep Guardiola at City, he will reject all other moves and wait to move as a free agent in summer. In that scenario, it could even prompt Arsenal to accept the £20m after all as they would otherwise get nothing from the deal.