Alexis Sanchez reportedly shook hands on a new Arsenal deal - then changed his mind.
The Chilean is out of contract next summer and looks set to join Manchester City.
Paris Saint-Germain are also interested in signing the forward.
But Sanchez is believed to have agreed a new deal 12 months ago but changed his mind when Arsenal were thrashed 10-2 on aggregate by Bayern Munich in the Champions League, according to The Times.
It is now up to Arsenal as to whether they hold on to an unhappy player or sell him to their Premier League rivals in January.
Sanchez's teammate Mesut Ozil is also out of contract in six months but is more likely to stay in north London.
Olivier Giroud's agent set for Arsenal crunch talks
Olivier Giroud's agent is due in London for crunch talks this week over the Arsenal striker’s future.
Giroud has started just one of the 15 Premier League fixtures he has been involved in this term.
And even though he has hit four top-flight goals – as well as three in the Europa League and one in a World Cup qualifier – he knows his lack of game time is hampering his hopes of starting for France in Russia in the summer.
Gunners boss Arsene Wenger has preferred to play Alexandre Lacazette, Giroud’s rival for the France No.9 shirt, through the middle for Arsenal.
Arsenal want Barca starlet
Arsenal are targeting a £17.7million move for Barcelona starlet Jose Arnaiz.
That is according to Spanish outlet Marca, who say the Gunners are seriously considering triggering the winger's €20million release clause.
Arnaiz, 22, came through at local side UD Talavera before earning a switch to Real Vallodolid in 2013.
Barca paid €3.4million for his services in August but he has been largely restricted to appearances for Barcelona B, scoring six goals.
He has appeared in the Copa del Rey, which has reportedly alerted and impressed Arsene Wenger.
Arnaiz penned three-year contract at the Nou Camp.