The Brazil international has been linked with a return to Spain this summer, just 12 months after he left Real Madrid.
“He will not come,” Guardiola is reported as saying by Spanish news agency EFE.
“He was Manchester City’s star signing last season and it would not make sense for them to part with him now.
“It would take something extraordinary for someone else to come in. I have a lot of faith in the young players coming through and prefer to work with them.”