The strength of Manchester City's squad has been demonstrated by Martín Demichelis dislodging Matija Nastasic, with Gaël Clichy also having lost his place to Aleksandar Kolarov.
Nastasic had an outstanding first season last year but injuries and the form of Demichelis, who signed in the summer from Atlético Madrid, mean the Serb faces a fight to regain his place in defence.
Manuel Pellegrini said: "Nastasic had two injuries. He's working very hard. And at this moment [Vincent] Kompany and Demichelis are the first choice but I am very happy with the whole squad. I can change them."
Of Kolarov, who has become a regular four years after a £19m move from Lazio, Pellegrini said: "He's in a very good moment but Clichy is also playing well. Clichy had an injury in his toes last month, we tried to give him a rest and now it's one of the positions of the team where I trust both of them. They are both very good performers.
"I see the full-backs as very important – they produce the space and to do that it's important they arrive at that exact moment. We've had five or six goals come from that side and also on the right. Pablo [Zabaleta] has three or four important assists, so both full-backs are very important."
City play Cardiff City at home on Saturday having totalled 99 goals in all competitions. If City score they will become the fastest team to a century. Pellegrini would be proud but "it can't be the most important thing to break records". He said: "What's important to me is that the team keep on playing in the same way. If we carry on in this way and score over 100 goals, then perfect but we are not trying to break a record. We are not going to go all-out attack just because we want to score 100 goals."
City train at the Etihad Stadium the day before every home match. Pellegrini believes this has been a factor in having won all 10 league games.
"It's important for the team to work one day at least on the pitch they will play on," he said. "I've done it everywhere I've managed. I think if you don't work often on your pitch, you do not get used to it. It's a small thing but I think it's a very important thing.
"We also have another pitch at Carrington that we train on – sometimes pitch two sometimes pitch four but I think training here [at the Etihad] is important – especially when it comes to set pieces."
Pellegrini confirmed that Yaya Touré and David Silva are available again after injury.