City are reported to have agreed a fee in the region of £43 million with Napoli for the services of the Italian international and a five-year deal is also said to be in place.
However, the finer points of the deal are still be hammered out between the two clubs and Santos says he is patiently waiting for a call from Napoli to give him the green light to conclude transfer talks.
That could come at any time and Santos says it is just a matter of sitting tight for now.
"Manchester City are working to close the deal with Napoli -- any moment could be the right one," Santos has been quoted as saying.
"The player is in Brazil. I'm in my house in England, waiting for a call from Giuntoli or De Laurentiis. When it arrives, I will go to meet the leadership of Manchester City."
City boss Pep Guardiola will be keen to get the deal in the bag sooner rather than later so he can move on and start securing his other transfer targets this summer.