City’s two senior centre forwards Sergio Aguero and Gabriel Jesus are currently sidelined with injuries.
Aguero missed the start of the 2020/2021 season with a knee injury suffered in the previous campaign. He returned after the recent international break but went off injured against West Ham United last weekend and is set to sit out another month on the sidelines.
Jesus is yet to return after suffering a muscle injury against Wolverhampton Wanderers in their opening Premier League game last month.
The Citizens will continue their Champions League campaign against Olympique Marseille on Tuesday and Guardiola has admitted he could be better served with another frontman in his ranks.
"Maybe, yes. We considered it, we thought about it, but we could not," Guardiola said at a news conference on the eve of City's match in the south of France when asked if he regretted not strengthening his forward line before the window shut.
"If you decide to buy a striker, it has to be a striker in the league of Gabriel and Sergio, but we cannot afford it.
"I am not saying the club didn't want to do it in terms of strikers, they want to make as strong a team as possible. Sergio is back [out injured], and I didn't expect Gabriel to be injured. Sometimes it happens."
He continued: "Sergio was injured last game. And you know, when you're four or five months out with knee problems, you are at risk.
"We didn't rush him back. We were incredibly patient, didn't force the doctors. Of course, we knew he was not in the best condition.
"But he was important against West Ham for 55, 60 minutes. Unfortunately, one action in the first half, he was unlucky, went to stop a long pass and he felt something. Hopefully, he recovers as well as possible.
"We tried to manage it as good as possible, but it was not enough to maintain it. We hope he will be back as soon as possible.
"I don't know long; it depends on the injury. The minimum is 10-15 days, a little longer. It could be a month."
