"Sincerely, before there was that possibility", he told TyC Sports. "I had a lot of problems that season, and small episodes after that with my knee, something always was bothering me".
But the Argentina global has been back to his best this season, scoring 30 goals to become the club's all-time record scorer despite a number of injury setbacks.More news: Boston Celtics: How to watch, listen and more
But Aguero said: "I think it's impossible".
Replacing him with someone of similar calibre would be far from easy, even for a club of City's resources, but it bodes well that Aguero is confident of staying put.
"He is going to stay at Barcelona, where he's playing well, and I'll do so at City".
Aguero, meanwhile, has admitted he would have missed the World Cup in Russian Federation this summer had he not chose to have an operation on his damaged knee.More news: Career-low round sees Marc Leishman lead in Dallas
"It's the first time in five years that I can flex my left knee well, without it hurting". "I tried to make an effort to play in the Champions League [quarter-final defeat against Liverpool]", he said.
"I said I preferred to do surgery because I could have missed the World Cup".
"Pep supported me a lot, told me to stay calm and after we lost in the Champions League I talked to the doctors and told them I did not feel well".
"After five years, my knee is like knew".More news: India declares 'conditional ceasefire' in Occupied Kashmir during Ramazan