The 26-year-old Geordie qualifies for Northern Ireland through his father who hails from Belfast.
Central defender Morris began his career in the North-East with Newcastle United but was released as a teenager and dropped down into non-league football with Blyth Spartans, Hayes & Yeading United and Morpeth Town.
He returned to the professional ranks four years ago, signing a one-year deal with Scottish First Division side Dunfermline Athletic before moving to Scottish Premiership side Dundee United in June 2014, but was released after they were relegated at the end of last season.
Morris signed a 12-month deal with Aberdeen over the summer but has yet to make his first team debut for the Pittodrie side due to injury.