Manchester City are to look to big-money signing Nicolas Otamendi as the side look to keep their five-game clean-sheet streak going against West Ham on Saturday.
Otamendi is likely to replace club captain Vincent Kompany, who suffered a calf injury in the side's defeat to Juventus in the Champions League on Tuesday.
Sergio Aguero returns to the side after only featuring for seven minutes of the Juve clash due to a knee injury.
"He is 100% and will play without any problems," manager Manuel Pellegrini said.
It will be the first time this season Pellegrini has changed a back four that has so far been near faultless.
Otamendi, a £32million buy from Valencia in the closing days of the summer transfer window, seems the most likely player to step in having come off the bench to replace the influential Kompany against Juve.
Pellegrini said: "It is always serious having injured players, especially the captain and especially in a moment when we didn't concede any goals in the first five games.
"I think it is important to carry on playing with the same names but I always say we have a squad.
"It is important for Nicolas Otamendi to have his opportunity to demonstrate why he is here and Martin Demichelis to return to his performance of last season. We have a squad and we need to replace the captain.
"Otamendi has been working with our team for the last three weeks - maybe not as much as we would like because he went with the national squad, but he is an experienced player, he must have his opportunity in this moment now. I hope he will have a good performance."
City have set formidable standards this season, with five successive wins opening up a four-point lead at the top of the table, and Pellegrini is hopeful they can be maintained in Kompany's absence.
He said: "Tactically we are working in exactly the same way that we did in the other two seasons but we are in a good moment because when individual performances are in a good moment, normally the team is also in a good moment.
"It is not easy not to concede one goal in the Premier League but we hope we can continue."
City are without Samir Nasri, Pablo Zabaleta, Gael Clichy and Fabian Delph for the clash.
The club's record signing, £54m man Kevin De Bruyne, could also make his first City start but Pellegrini, speaking at his pre-match press conference, was non-committal.
West Ham go into the game in good spirits after beating Newcastle on Monday while they have also notched up a couple of notable away wins.
Pellegrini said: "West Ham are doing very well this season, especially playing away. It is not easy to win two games against important rivals like Arsenal and Liverpool without conceding a goal.
"They have nine points in the table - a good total - good players and they are playing very well.
"We know we must be very careful about the counter-attacks and very careful about the set-pieces and try to be a balanced team during the whole game."