Mario Balotelli is likely to leave Nice at the end of the season after the club's president revealed he is unlikely to be offered an extension.
The controversial Italian found the net 33 times in his first two seasons in Ligue 1 but has so far failed to replicate that form under new boss Patrick Vieira.
After 10 appearances and no goals this season, he appears set for the exit door at the club.
On the possibility of a new deal, Rivere said: 'An extension? No I think it will be over.'
'Mario, for us, was leaving [last summer] so he missed his preparation,' Rivere told RMC Sport. 'I think every player that misses his preparation suffers for the first part of the season.
'Now he has recovered his physical aptitude, but he's not in luck (in front of goal). So the poor guy is frustrated.
'But Mario didn't lose his talent (overnight). The day one goes in, then the goals will keep piling up. Let's not have any regret'.