The 21-year-old failed to win a contract at Dundee United in April and is now trying his luck with Kilmarnock, flying out with the club on their pre-season trip to Italy.
Killie boss Jim Jefferies confirmed that Thomas is one of two French forwards currently on trial with the Rugby Park outfit.
"They're in their early twenties so I'll have a close look at them before deciding whether to take things further," he said.