Man City suffer Balotelli injury blow
"I'm worried because he can't play for another three or four weeks at an important moment for us," Mancini was quoted as saying on the BBC. "To have an operation done and then to have another problem two months later is strange."
The 20-year-old Balotelli's season has already been disrupted by injury and suspension and he has made just seven Premier League starts since joining from Inter Milan.
"He may need surgery. We just don't know. He must rest, then he will have treatment and work. Hopefully then he will be OK," added Mancini, who can at least content himself with the knowledge that new signing Edin Dzeko will be available for Saturday's home game against Wolverhampton Wanderers.
Dzeko, who gave his first news conference on Tuesday since signing in a reported 30 million pounds deal from Wolfsburg, is likely to start alongside Carlos Tevez against Wolves.