I cannot say that I’m familiar with the regular thoughts and dilemmas of professional football players. So all I can do is speculate. But if a player decides to leave (unless of course it is all fake news) that is generally not a good sign.
What has happened that he doesn’t want to stay any longer? Possible answers and examples (excluding those where the club initiates the transfer like Szczesny’s or Iwobi’s case):
A) a major club wants to buy you, and you couldn’t say no (Ox, Vermaelen)
B) you finally have a chance for silverware (van Persie, Sanchez)
C) you don’t have enough game time and look for less competition and more guarantees (Martinez, Gnabry, Malen)
D) you have won (almost) everything, and you need new challenges, a different football culture (Henry, Fabregas, Gabriel)
E) you primary want 30% higher salaries (Nasri, Hleb)
F) there is a major conflict between you and somebody from the team or staff (Adebayor, Torreira, Guendouzi)
G) finally you can play for your boyhood dream club, or your coach idol (Fabregas)
H) you feel that others get unfairly high salary compared to yours, so the only way to ‘restore justice’ is to run down your contract and move on a free transfer with astronomical wages (Ramsey, Sanchez)
I) you no longer want to compete on the highest level, and/or would move back to your home country (Monreal, Koscielny, Cazorla)
J) you feel seriously underappreciated, and treated unfairly by the fans
Out of these 10 scenarios Xhaka’s rumored Roma move would disqualify 8 of them. F) and J) are possible, but we don’t have data on the former, and there is little evidence that any player has ever left due to fan treatment only, as long they were appreciated professionally (playing minutes) and financially (weekly salary and bonus).
So over to you fellow Gooners: why would Xhaka want to leave our fab club?