Nasri missed the 7-0 Capital One Cup victory over Sheffield Wednesday in midweek due to a groin problem. And after confirming the 27-year-old Frenchman will not be featuring in Saturday’s Barclays Premier League match at Hull, Pellegrini said: “It’s serious because maybe he will have surgery in the next days. Manchester City midfielder Samir Nasri is set to undergo surgery on his groin and is expected be out of action for a month, Blues manager Manuel Pellegrini has revealed. The Chilean said: “Mangala worked a lot with us before he made his first start. I think that was very important for him. “Maybe some people were not patient about why he didn’t play before but that was the best way to bring him into the team. I think in both games he did very well.” Ahead of the Hull match City are sixth in the table, five points behind leaders Chelsea, and Pellegrini is in no doubt his side – the reigning champions – need to stop dropping points. But he has stressed he is not worried about how they have played so far this term, and also feels it is useful that there are players in his squad who have been through an unsuccessful title defence, under Roberto Mancini in 2012-13. Pellegrini said: “I think it’s good experience. “When you win the title, maybe it’s more difficult the next year to have the same motivation but what I feel here in my team is that that experience was useful for the players. “They are trying to do their best. The challenge not only to win the title but to continue winning titles is very important for this group and I hope we can celebrate another title at the end of the season.” Press Association “I’m not a doctor but I think he will be out for around one month. “He was training but he wasn’t 100 per cent. He didn’t feel comfortable with what he was doing so the doctor decided that was the best option. “Of course he’s a very important player for us and it’s not easy for us to play without Samir. “But I never give excuses about players that, for different reasons, are not in our squad. We have an important squad.” City are also currently without midfielder Fernando (groin) and striker Stevan Jovetic (hamstring), although Pellegrini said of that pair: “Both of them, I think, will be ready next week.” Striker Sergio Aguero and playmaker David Silva are back available for Saturday’s contest after knee and ankle problems respectively, along with Pablo Zabaleta following the completion of his suspension. Big-money summer signing Eliaquim Mangala will be looking to keep his place at centre-half having come into the team for the last two games. Pellegrini would not be drawn on whether he views the 23-year-old France international as a long-term first-choice, but he has been impressed by the start Mangala has made.