The midfielder revealed his intentions prior to City's game at Atletico Madrid in the second leg of their Champions League quarter-final on Wednesday.
Fernandinho, 36, signed a one-year contract extension with City last June.
Asked if he expected to still be at Etihad Stadium next season, he said: "No, I want to play regularly."
Fernandinho has won four Premier League titles, one FA Cup and six EFL Cups since joining City from Shakhtar Donetsk in 2013.
He has made 23 appearances for the club this season, but started just six times in the Premier League as the club bid to retain the title.
Fernandinho added: "I will go back to Brazil. I decided with my family, which is the most important for me."
Guardiola, whose side take a 1-0 first-leg lead into the return against Atletico, spoke after player in the build-up to the game.
"I didn't know it," said the City boss, when asked about Fernandinho's comments. "We will see what happens at the end of the season. We don't know what's going to happen.
"Fernandinho, I've said many times, is so important for me. We will see what happens but, anyway, I will talk to him.
"Maybe it's a family decision or maybe he wants more minutes than he has had this season, I don't know.
"I will speak to him, of course, but this kind of situation...at the end of the season we are going to talk."
Guardiola praised club captain Fernandinho's influence as he added: "I know what he has done, behind me, he handles many of our players and stars for the benefit of the team.
"An incredible player for Manchester City. There are things nobody knows but I know exactly what he has [done].
"I've said many times that I want the happiness of my players. We are going to play tomorrow for him and give him the best farewell moment, reaching again the semi-finals of the Champions League and, after, trying to go through again."
Following the news conference, Fernandinho put a post on social media saying he had been "100% honest and spontaneous" in answering questions put to him.
But he added: "Anyone who knows me also knows that my greatest honesty is with Manchester City and my duties as team captain.
"My focus is 100% on winning all the titles we are playing for and I will only talk about my future at the end of the season. Let's keep pushing!"
-- Courtesy of BBC Sport