MANCHESTER -- Pep Guardiola has refused to rule out a return for Joe Hart to his side despite dropping him for his first game in charge.

The England keeper was surprisingly left out of the starting lineup in favour of Willy Caballero for Manchester City's 2-1 victory over Sunderland at the Etihad.

City have been repeatedly linked with a move for Barcelona keeper Marc-Andre ter Stegen and the decision to leave out Hart won't quieten any rumours that Guardiola is interested in bringing a new keeper.

However, the manager played down the decision and says the 29-year-old could start City's Champions League playoff first leg clash away to Steaua Bucharest on Tuesday night.

"Of course he can play -- all the players in the squad can play," Guardiola told a news conference. "Normally I have a good staff. When we have a game I just focus on this game. I never see one game from the next.

"I was Sunderland, Sunderland, Sunderland, what we had to do. From now on until tomorrow morning I am going to decide what is the best for the team.

"I think Willy make a good preseason -- really, really good. He gave me today a lot of confidence for his build-up play, for his personality and that's why I chose him."

Hart wasn't the only high-profile player to be left out with Yaya Toure, Wilfried Bony, Samir Nasri, Eliaquim Mangala and Jason Denayer all missing from his 18-man squad.

Pep Guardiola his squad could see a heavy amount of rotation this season. Photo by Stu Forster/Getty Images

Guardiola admitted ahead of the Sunderland game that he needs to trim his first-team squad but he insists that all his players could still have a future at the Etihad.

"I don't have any complaints about these names," he added. "Yaya trained really good. Sammy arrived a little bit -- but the last one week, two weeks he is training amazing. So I am really impressed with the quality of Sammy. Mangala you know better than me how professional he is.

"But in the end I have a squad and I decide what I see I have to create a team spirit. It's not about tactics, it's not about anything. And I decide today for this lineup, that does not mean in the future they are not going to play or they are going to play.

"At Barcelona and Bayern Munich I wanted to change the lineup because always I want to involve, I want to create something where everyone is involved."

Guardiola was relieved to pick up three points from his first Premier League game. Sergio Aguero's third-minute penalty was cancelled out by a Jermain Defoe strike in the second half before Sunderland defender Paddy McNair headed into his own net for a fortunate winner.

Guardiola had demanded that his side played with "soul" and he felt that his side delivered as they pushed until late into the game before finding a second goal.

"The spirit was perfect," he said. "I said many, many times I've seen good things about the team and the spirit. That's why I am so pleased -- because we have to build something from that to be a team to defend.

"Their body language was correct to defend the last ball with their lives and not conceded a goal. That is the first step and after we can talk about the tactics, the performance, play good or play bad, everything can happen."