Celtic loanee Olivier Ntcham was "starting to stagnate" at Parkhead according to former teammate Christopher Jullien.
The French midfielder joined Marseille on deadline day and made his debut for his new club in the French Cup victory over Auxerre having been used sparingly by Neil Lennon this term.
Hoops' centre-back Jullien felt it was the right time for the 25-year-old to leave the Scottish Premiership and expects the midfielder to show his quality in Ligue 1.
Jullien told French outlet La Provence when asked about Ntcham: "He had taken a step forward in Glasgow but he was starting to stagnate, because he remains in Scotland.
"He needed a new challenge. I see him succeeding at OM, he has everything he needs to achieve this.
"This stage will be able to make him grow even more. He has always had the qualities to aim for a major championship like Ligue 1."
Jullien also heaped praise on the ability of Ntcham and his attitude behind the scenes at Lennoxtown, although admitted his countryman gave him "problems" on the training pitch.
The towering defender added: "He wants to play everywhere, to bring his technical touch.
"Sometimes, in training, he gave me problems because I wanted to win and he just wanted to play.
"He was our technical leader. He was never a guy who spoke a lot, but a leader in the field by his actions and his technical touch. "
