Manchester City manager Roberto Mancini has warned Mario Balotelli that it is time to grow up as he considers handing the controversial striker a recall when the champions face Liverpool today. With City striker Sergio Aguero sidelined for at least three weeks after the Argentine suffered a knee injury against Southampton last week, Balotelli may start at Anfield. Mancini knows it is always a risk to field the volatile Italian, who was sent off after two yellow cards in the space of 18 minutes following his introduction as a second-half substitute at Anfield last season. When the former Inter Milan striker was sent off again later in the season against Arsenal, Mancini claimed Balotelli might never play for City again. However, Balotelli, 22, impressed at Euro 2012 as Italy reached the final in Poland and Ukraine, leading some to believe he had matured at last. Mancini has always admired Balotelli's talent, but he insists he still has a lot to learn if he is to become a main player for City. "I think that Mario has a big responsibility because for us he's an important player," Mancini said. "In two years he won Premier League and FA Cup, I think that he did well. I agree that if Mario plays always like he did at Euros it will be better. "Mario is the same. I don't think that he can change in one month. Probably this season can help him to improve. "The European Championship is like the World Cup, one month. Every player goes 100 per cent. Mario is an important player also here. I think he can do better but I'm sure that he'll improve." Gareth Barry and Micah Richards have joined Aguero on the treatment table ahead of the trip to Liverpool and Mancini admits his focus will turn to adding two or three more players to his squad once the game with the Reds is out of the way. The Italian knows he needs a big enough squad to attack all four competitions this season, with the Champions League a big focus. He has until Friday to bring in new recruits before the transfer window shuts until January. "We have 19 players at the moment and two or three players injured. It's impossible," he said. "The reason I want to improve the squad now is because I want to improve for the Champions League." After last weekend's disappointing 3-0 defeat at West Bromwich Albion, Reds manager Brendan Rodgers is hoping his side can kick-start their campaign with a win over the reigning champions. "We know that if we are going to have any sort of success this year, we've got to make sure we can win as a many of our home games as we possibly can," Rodgers said. "Manchester City are the benchmark, they are the champions and it's going to be a really difficult game. "But my players are really focused and looking forward to the game. Anfield is somewhere we want to make sure is a real fortress and there's no better game to start working towards that than against the champions." Andy Carroll may feature despite rumours about his future after he missed Liverpool's Europa League win over Hearts on Thursday with an injury.