He didn't want to stay here, it's very doubtful he'd want to come back.
People keep saying this but it doesn't really make sense.
He didn't want to stay here because he knew he'd not get game time, be held back, and the club were falling over themselves trying to buy Sanchez.
If he came back like Pogba with a club record fee, he's no longer have to worry about getting game time or his career progressing.
The only reason he left would be not be an issue.
The much bigger reason he won't come back is because we just filled our wing vacancy with Mahrez, a club record signing who seems to be settling in well.