The Italian had hoped to rest the Argentina international, who has been a key figure so far this term, for their next Europa League clash.
However, with doubts over Jo's fitness, Roque Santa Cruz unavailable and Mario Balotelli out, Mancini is short of options.
"We must see if Jo will be available, but most of the others are okay," Mancini told the club's official website.
"Only Mario and (Aleksandar) Kolarov are out, but probably are fine for the next game. Kolo is not available either for Poznan.
"I will only decide on whether I rest Carlos after training (on Thursday).
"We will probably make changes because after the Europa League game we only have just over two days to recover for Arsenal, so we will make changes because of that. But we want to win on Thursday, it's an important game for us.
"I am happy with Manu," he continued.
"At the moment we only have Manu, Carlos and Jo to choose from because Roque is not on the list for European games.
"We will have to wait to see if Jo recovers, but I was happy with the way Manu played at Blackpool."