Valbuena sidelined with knee knack
"Mathieu Valbuena sustained a pretty serious knee injury during training on Saturday morning," OM said on their website.
"He will take some tests on Sunday morning to get a precise diagnosis. He will out for several weeks."
Valbuena looks set to miss Marseille's Champions League last 16, first leg tie against Manchester United on February 23 at the Stade Velodrome.