Pep Guardiola believes Manuel Akanji will be the "perfect" fit for Manchester City after signing the Switzerland defender from Borussia Dortmund on transfer deadline day.

City responded to Guardiola's concerns about the fragile fitness of his centre-backs by paying £15 million to bring Akanji to the Etihad Stadium on a five-year contract.

The 27-year-old will provide valuable cover for Aymeric Laporte and Nathan Ake, whose recent injuries highlighted the need for central defensive reinforcements.

"We had four incredible central defenders before Manu but sometimes Ayme had tough injuries. He's getting better but a month or month and a half still there sidelined," Guardiola told reporters on Friday.

"Nathan had in the last month some concerns about muscular problems, so we've just had two central defenders with this incredibly busy schedule that we have ahead of us.

"We had an opportunity to bring one player, only a year left on his contract in Dortmund, with a lot of experience in Germany and the national team with Switzerland.

"He suits perfectly what we need. He's fast and really good in the build-up.

"We knew it, we felt it, when we played against Dortmund two or three seasons ago and, yeah, very pleased he's here and good competition for central defenders."

Ake could be in line for a return to action in Saturday's trip to Aston Villa, but Laporte is unlikely to be back from a knee injury until October.

"I said one month ago it would be end of September, October. I think he will be ready maybe after the international break, he'll start to be ready," Guardiola said.

"I cannot forget being in that position and the problems playing West Ham away and the final game against Aston Villa, we didn't have another alternative because Ruben (Dias) was injured, Nathan was injured.

"This is the other reason why we decided to go for Manu Akanji but we'll be fine.

"But after surgery it's time, so end of September, beginning of October. It was a bone (issue) but I'm not a doctor."

Akanji will hope to be involved against Villa, but all eyes will be on his former Dortmund team-mate Erling Haaland after he scored hat-tricks in City's last two matches.