Steven Mouyokolo has been training with Celtic as part of a trial with the Scottish champions.
The defender is available after leaving Wolverhampton Wanderers in January, following a series of injuries during his time at the club.
Celtic coach Danny McGrain told reporters: "He's here until the end of the week. He doesn't look strong but he's tall with a good physique.
"He's not a Bobo Balde type. But we haven't had a game situation yet, defending corners and free kicks."
The Frenchman also had a previous spell at Hull City.