The news will increase speculation that the 29-year-old will join Blackpool, who were defeated by West Ham in last season's Championship play-off final.
Barton had spent pre-season with League Two new-boys Fleetwood after being banned for QPR's opening 12 Premier League matches of 2012/13 as a result of his violent conduct at Manchester City on the final day of the last campaign.
A loan to Fleetwood and their packed fixture list, which begins against Nottingham Forest in the Capital One Cup on Monday, would have reduced the timescale of Barton's ban and seen him return from suspension by the end of September rather than November.
But Fleetwood boss Micky Mellon has ended his interest in the midfielder, who was also stripped of QPR's captaincy and fined six weeks' wages as a result of his behaviour against City, after being told Barton would not play in League Two.
"Joey has gone back to QPR," Mellon told Sky Sports. "His influence in and around the football club was nothing more than fantastic.
"(He was) a great lad, up to standard for us, players saw how hard you have to work to be a Premier League footballer.
"Nothing but positives came from the time we had with Joey. We always knew it was going to come to an end at some stage.
"We did try and get him on loan. QPR did not want to do that. He has gone back to QPR and we wish Joey all the best. He will always be a friend of this football club."
Barton later confirmed on Saturday afternoon he had left Fleetwood and wished the club all the best for the new season.
He said on Twitter: "Fleetwood adventure is over. I loved every minute of it. Great club. Good luck to @capboy70 (Fleetwood chairman Andy Pilley), Mickey and a great set of lads for the season."
Reports had claimed Ian Holloway's Blackpool, who have also been linked with former England international Emile Heskey, will instead win the race for Barton.
Mellon, though, could not shed any light, as he said: "I do not know anything about any clubs. That will be up to Joey and QPR now."
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