Tevez returned from a month-long hamstring lay-off in City's crucial win over Tottenham on Tuesday but featured for only 12 minutes at Eastlands.
Mancini insisted the Argentinian would not be rushed but was upbeat about his progress when quizzed on Thursday.
"Carlos is getting better - we have another two days to decide whether he can play or not," Mancini said.
"At the moment I don't know. We will see what happens after these two days and decide on Saturday morning."
Another doubt surrounds Gareth Barry, who has missed two games with his own hamstring problem, but the Italian coach believes the England international will be available.
"Gareth will be okay," he said. "He trained with the team yesterday."