Barton has been absent from Rangers training since late last week after reportedly being signed off with stress.
Now it appears his ill-starred spell as a Rangers player is over.
The midfielder has a year and a half remaining on his contract but a deal to terminate the deal has been agreed and is expected to be confirmed on Wednesday.
Barton concluded a six-week suspension last week, imposed for rowing with manager Mark Warburton in a training ground bust-up. However, he was told to train with the under-20s.
He trained for one day with the youth players before getting a doctor’s note from his GP, according to reports.
Barton is expected to return south of the border in search of regular football, while Rangers will look to use the freed-up wages to strengthen in January.
The midfielder also faces an SFA charge for gambling offences having placed bets on 44 matches while with Rangers.