The Spaniard feels that his former team-mate should not have been allowed to leave and his departure has contributed to his side's appalling run of form in recent months
The Argentine playmaker returned to his former club, Porto, and the 22-year-old feels that his former team-mate's departure has contributed to his side's appalling run of form.
"Since he left, we've only won the [home] match against Inter. He was very important for us in the dressing room," he told RMC.
"Even if he wasn't on top form on the pitch, he gave it his all and remained professional. He never said a bad word. His departure was very bad for the group.
"It could be a coincidence, but the numbers are there."
Meanwhile, Andre-Pierre Gignac has hit out at French broadcaster Canal Plus for fabricating an argument between himself and Didier Deschamps after he was substituted during Wednesday's loss to Montpellier.
"An argument about nothing! Canal + has invented my words. This argument doesn't exist. End of."
Marseille are without a league win since the end of January and have slipped to ninth place in the Ligue 1 table.