A free transfer after his release from Juventus, Rabiot joined OM after being rejected by several Premier League clubs.
De Zerbi said: "We need two, three, four or even five Rabiots. I asked him if he had a brother like him, but he told me he doesn't play football!
"Whether he scores or not, he's still a decisive player for us. We want everyone to improve their stats. Because of his quality and his characteristics, Adrien has this ability to score. He must exploit it, but it mustn't become an obsession.
"The forwards obviously have to do more, even (Mason) Greenwood who has scored 10 goals must aim to score 20 or 25."
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