The 28-year-old is expected to leave Barcelona this summer, as he only has a year left on his contract.
“Eto’o has a stratospheric offer from City, which would convert him into the best paid player in the world,” Laporta told Catalan radio station iCat FM.
“It’s starting to become clear that he has this monster offer. He wants to stay but an offer like this is very difficult to refuse.
“If Eto’o accepts this stratospheric offer we will have to bring in someone.”