Montolivo says the locker room also believes in August signing Alessandro Matri.
"Kaka can give us something more in terms of experience and personality. He can add quality to our side and I am sure he will achieve great things with us.
"Kaka is priceless and he will give us a hand on the pitch," said Montolivo.
"We have lots of faith in him and also in Matri. He hasn't as yet found the net, but his performances have always been good.
"We play with one forward who is always surrounded by defenders and he works to support the team. He has always scored goals and he will start hitting the back of the net. He does not need to worry."
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