And Guardiola said the decision was partly down to the availability of Laporte, who has not played this season after undergoing knee surgery in the summer.
“We have four incredible centre-backs before but sometimes we’ve had it tough with injuries,” Guardiola told a news conference on Friday.
“Some are getting better but a month or month and a half [for Laporte] and Nathan [Ake] could not play [the last two games].
“So we’ve just had two centre-backs. We had an opportunity to bring him [Akanji], one year left in Dortmund, a lot of experience, he’s perfect for what we need and we’re very pleased to have him here as competition.”
City have relied on John Stones and Ruben Dias in the last two games against Crystal Palace and Nottingham Forest and they are likely to be paired together again for the trip to Aston Villa on Saturday.
Guardiola is not expecting to have Laporte available until after the international break at the end of September but the 28-year-old could possibly return for the home game against Manchester United on Oct. 2.
“If I say one month [out] it would be the end of September, October,” the City manager added.
“I think maybe after the international break [he could return]. He will not force it. I cannot forget being in that position — West Ham away and the final game against Villa last season — we didn’t have another alternative and he had to play.
“This is the reason we’ve gone for Akanji. After surgery it needs time.”