Guillem Balague says "half the team" will be replaced by Guardiola.
He said: "Quite clearly Pep Guardiola is going to use the last two years of his contract - which will probably be the last two of his career as a club manager - to prepare a new Manchester City.
"I have got a very clear idea that they will want to get rid of five or six regular starters for Manchester City and bring in five or six new starters.
"Half of the team. It is a new era. The end of this one and a new era starting."
Balague also lifted the lid on the scratches that have appeared on Guardiola's face in recent weeks.
Speaking before today's defeat at Aston Villa, he said: "(Pep) is protected by his people but he senses a lot of people want Manchester City to fail. The day before (against Feyenoord) there was an argument - but a football argument - about positional play and where he had to play with Kyle Walker. And he just got nervous and he marked his nose and they put a cover on it. It was in his own office.
"It shows that he is tense and he is nervous of course. You know he doubts hugely in himself, he always has. He thinks 'I'm not going to be able to figure this out' and he needs the support of people. And quite clearly he has the support of people and quite clearly he will find a solution."