The Rangers winger is being allowed to leave the club to gain experience next season, and the League One side are lining up a move according to the Daily Record.
Middleton's preference for a loan move is England, having joined the Ibrox side from Norwich City in January 2018.
With Daniel Candeias, Jordan Jones and Jamie Murphy, plus the possible double addition of Ryan Kent and Sheyi Ojo, Steven Gerrard doesn't want the 19-year-old's development stunted. The same goes for Jake Hastie.
Middleton made 29 appearances in the season just past but only eight starts and he will likely find game time even harder to come by in the upcoming campaign.
The player added more fuel to the speculation fire by following Doncaster Rovers on Twitter.
The Yorkshire side are looking to push on under Grant McCann after finishing in the play-offs last term.
They have lost key player Mallik Wilks who has returned to Leeds United.