Rangers following his Leeds United exit. The Scotland cap is out of contract at Elland Road having spent last season on loan at Blackburn Rovers in the Championship.
The 31-year-old left Scotland after spells with Dundee United and Queen's Park in Scotland, making moves to Lech Poznan in Poland and Konyasport in Turkey.
He would eventually move to England and earned promotion with both Wolves and Leeds United, before being loaned back to the Championship by Marco Bielsa for the final year of his deal.
Left-back Douglas was keen to remain in England or move to the Scottish Premiership due to his family situation as he weighs up his options.
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