Middleton joined the Gers from Norwich City in the summer of 2018 and the 22-year-old has spent the majority of his time with Rangers going out on loans.
The 22-year-old is now set to end his association with the Ibrox side as a move to Dundee United is in the offing.
Dundee United boss Jack Ross is an admirer of Middleton and they previously worked together when the player was on loan at Hibernian.
It has been claimed that a deal has been agreed between Rangers and Dundee United regarding the player’s transfer fee.
And the 22-year-old will undergo his medical today and join Ross’ squad for their Scottish Premiership game against Kilmarnock.
Middleton would be the Terrors’ sixth summer signing and Ross indicated that he wants to add more options in midfield before the Europa Conference League clash against AZ Alkmaar on Thursday.
The Terrors finished fourth in the Scottish Premiership last year and earned a Europa Conference League qualifying spot.
