Armenian international Gael Andonian has been on trial at Sunderland in recent weeks as the club weigh up whether to hand him a contract, Chronicle Live reports.
Sunderland gave the defender his first outing in Premier League 2 game against West Bromwich Albion at Eppleton.
The 23-times capped France-born Armenia international lined up at centre-back alongside summer recruit Jack Bainbridge.
Sunderland manager Jack Ross and his coaching team of James Fowler and John Potter were in the stands to watch the 23-year-old in action, as were academy manager Paul Reid and head of recruitment Tony Coton.
He is out of contract and available as a free agent after leaving French giants Marseille in the summer, which means he can be signed outside the transfer window.
He has made only one senior appearance for Marseille – coming off the bench to replace future Newcastle United man Florian Thauvin in a 2-1 home win over Lens in November 2014 – but went on to play at Ligue 2 side Dijon on loan, and also had a loan spell in Greece with Veria.
Andonian represented France at U16 level in two friendly games before opting to represent Armenia as a senior international.