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Balotelli has struggled to find form in the Premier League this year.
Mario Balotelli walking straight to the tunnel after his substitution can be blamed on both petulance and frustration.
Balotelli thinks very highly of himself, so his poor performance for 55 minutes last week will have annoyed him. He expects more, and with good reason.
He has immeasurable talent, but still doesn’t seem to understand that if he plays badly he will be substituted. Mancini’s decision to bring on Aguero was vindicated almost immediately when the Argentinian linked up with Tevez and finished in style.
Aguero continued to show his understanding with Tevez and City’s attack looked genuinely lifted as soon as he came on.
The problem with Balotelli is that he lets everyone know of his frustration, which rubs off on his teammates. Mancini may have a huge amount of patience with him, but it’s not everlasting.
At some point, Balotelli will have exhausted all his sympathy and that will spell the end of his City career.
There are some people who believe that should be sooner rather than later, especially considering he looked to have turned a corner during Euro 2012. That sort of consistency is maddeningly just out of reach for him, which is as much a problem for Mancini as for the striker.
It’s not time for Balotelli to leave the Etihad, but it is time that he understood his role within the team. He has to know that he won’t start every game, just as he has to know that he won’t finish every game.
He may think he is the best player on the pitch at all times, but that has to be demonstrated in his results. That means goals, and at the moment he isn’t delivering.
His last Premier League goal was in March, so he has no right to so openly condemn his substitution. It may simply be frustration with himself, but walking straight down the tunnel doesn’t immediately suggest that.
Along with Aguero, Edin Dzeko has also impressed after coming on as a substitute, but those good performances seem to desert him when he starts.
Dzeko is best used within this role, as his game isn’t suited to linking up with Samir Nasri, Aguero nor Tevez. He drifts in and out of the game and often looks at odds with City’s crisp play.
What Dzeko does best is change the tempo of the game, usually by replacing either Tevez or Aguero. This is the best way to score quick goals as the defence doesn’t have time to adjust to Dzeko as he enters the fray.
Although he would no doubt want to start, his propensity to score quick goals means he is ideally suited to his current role.
Aguero and Tevez are the proven performers of this year, and deserve to keep their place in the starting lineup, whereas Dzeko is already in an impact-player position that suits his style.
The rumours about signing Falcao won't go away, but Dzeko keeps scoring goals, which is all that matters.
Of course, that leaves Balotelli. He is a huge asset to the team, but until he starts finding the net again in the EPL, City can’t afford to keep starting him.