The AC Milan forward says that the thigh injury suffered by his newly re-signed compatriot has been a contributing factor to the Rossoneri's disappointing form of late
Massimiliano Allegri's men sit ninth in the table after six games, with Kaka having managed just one appearance since arrivng from Real Madrid in September.
And Robinho believes that the Rossoneri could have enjoyed a better start to their campaign had his countryman not picked up a thigh injury immediately following his return to San Siro.
"Kaka is a personal friend to me. He's a great player, I hope he can come back as soon as possible," the attacker told La Gazzetta dello Sport.
"We miss his quality so much; he is a decisive player."
Milan face champions Juventus on Sunday but will also have to do so without striker Mario Balotelli through suspension after the forward's red card in their defeat to Napoli.
The Italy international has three goals and two assists to his name in Serie A already this season and Robinho says that he will be missed.
"He is a champion; he makes all the difference," the 29-year-old added. "He's a very strong personality on the field; he's very special."