Fleetwood scored twice in seven games for Cheltenham, but failed to find the net in any of his final three games - against Scunthorpe, Tranmere Rovers and MK Dons.
But Fleetwood, who moved to Valley Parade from Forest Green in the summer but has not made a first-team appearance for the Addicks, was not surprised by the manager Martin Allen's decision.
"Martin told me on Sunday night that I'd be heading back to Charlton," Fleetwood told Charlton's official website.
"Things started well, but the last three matches have definitely been quieter for me and I am not sure why. I have not been at my best and I am sure that had a bearing on Martin's decision."