Keeping Alexis Sanchez at the Emirates Stadium this summer could be considered bigger than any signing Arsenal make before the transfer window shuts.Sanchez, Arsenal’s Player of the Season in two of the past three seasons, is out of contract next year and doesn’t appear close to penning an extension on his current deal.But Arsene Wenger isn’t ready to sell the Chilean in this window. He would prefer Sanchez to leave on a free in 2018 rather than cash in now.Which makes sense considering Sanchez’s importance to the Gunners, although it must be discouraging for the club knowing that the 28-year-old doesn’t want to stay.He’s been linked with moves to Manchester City and Chelsea, although Wenger doesn’t want to sell to a Premier League rival. Meanwhile, it’s unclear whether Bayern Munich are willing to meet Sanchez’s exorbitant wage demands.Until he’s spotted signing a contract with another club, Sanchez remains an Arsenal player. And, after being granted an extended break, he’s due back for training on Sunday.But Sanchez’s return may be in doubt following his latest Instagram post.

Sanchez's Instagram post

The former Barcelona winger took to social media to post an image of himself with his dog - of course - writing: “sick”. Just two days before he's set to make his return? Arsenal fans aren't happy. 

Too sick to play football? That much is unclear. But Sanchez’s post got a reaction from Arsenal’s fans on Twitter.

Expected return on Sunday

Arsenal will play in the Emirates Cup this weekend and while his teammates are battling Sevilla on Sunday, Sanchez will be returning to match practice.

"Alexis and Mustafi, their first training session will be on Sunday, the day we play against Sevilla," Wenger said this week, per the Mirror.

Wenger: 'He is not for sale'

Another club rumoured to be in for Sanchez is Paris Saint-Germain, although Wenger believes they have turned to Neymar because they cannot sign the Arsenal star.

"Paris Saint-Germain cannot get Sanchez so they go for Neymar,” the Arsenal boss said, per Goal.

"I read L'Equipe in the last three or four days. It has moved from Sanchez to Neymar. Today they speak about Neymar, three days ago they speak about Alexis. They need as well, like you [reporters], subjects.

"My mind has been made up for a while now. I think I've made it clear a few times that he is not for sale and this is my stance."

Should Arsenal cash in now or let Sanchez leave in 2018? Let us know in the comments section below!