The 29-year-old's future with the west Londoners has been the subject of much debate this summer after he was stripped of the captaincy and given a 12-match FA ban for his red card and subsequent conduct on the final day of last season at Manchester City.
Barton spent pre-season training with Fleetwood, but would not be able to join League Two newboys on loan as it is understood the Football League would refuse to register him while his ban remains.
However, the fact he was not given a squad number by QPR has done little to suggest he has a future with the club and Press Association Sport has since learned Marseille are interested in the former Rs skipper.
The Ligue 1 club have yet to table an offer, though, and are thought to be the only club to have expressed an interest in the former Newcastle man.
Barton, perhaps teasingly, wished his Twitter followers "Bonne nuit" - French for "good night" - on the social media network on Thursday evening.
Earlier, upon finding out his old number 17 shirt was given to summer signing Nelsen, he posted: "Heard my shirt numbers gone to someone else. News to me..."
"Just come off the golf course so only just heard. A call would of [sic] been nice. Ah, well life goes on..."