Manchester City manager Roberto Mancini tells defenders to adapt or sit in the stands Roberto Mancini risked stirring further unrest among his Manchester City squad by insisting that those who do not fall into line with his methods have a limited future. Micah Richards, who suggested his fellow defenders were unhappy with the way City resorted to a back three in the catastrophic defeat to Ajax on Wednesday, was told he could expect to watch from the bench if he did not understand the system. "With this system we have got a result every time," Mancini said. Maybe Micah doesn't know this because he has been out for two and a half months. He has probably worked on it less than other players but the next time we play this system Micah can stay on the bench and we will use another player who understands the system. Mancini's observation that three central defenders "get a result every time" does not bear much scrutiny. The results they achieved against first Liverpool and then Aston Villa were a 2-2 draw and a 4-2 defeat that pitched them out of the League Cup. Nevertheless, Mancini made it clear that he expects some highly-paid defenders to be able to adapt to their manager's instructions. "If you are a top player, it is not important what system you use," he said. If you don't understand that, then you are not a top player and you cannot play for a top club. Facing yet another failure in the Champions League, a competition in which he has never gone past the quarter-finals as a manager, Mancini, whose side face Swansea at home today, was as agitated as many had seen him at a press conference. When it was suggested to him that it was not a coincidence that City's defensive performances had begun to slide since the appointment in the summer of Angelo Gregucci, who speaks no English, as a defensive coach, Mancini said "stop, stop, stop" before pointing out that Gregucci had taken "maybe one" session. Nevertheless, it may be significant that the men who appear most unhappy with City's direction are English - Joleon Lescott, Gareth Barry and Richards. However, if there is dressing-room unrest as some have alleged, the man who brought the first championship to the club since 1968 appears indifferent to it. "People tell me what is in the newspapers yesterday and this morning but I am not frustrated by it and I am not interested in it," Mancini said. I respect your job but I have my opinion about everything. My head won't go down after one or two defeats. I give my opinion and, like everyone else, I can make a mistake.