Since taking over in 2008, the 40-year-old has led the Catalan side to two Champions League and three consecutive La Liga titles.
Despite this success the former Barca midfielder has always managed the side on a season-by-season basis, leading to constant speculation about a move away from Barcelona.
However, Guardiola has said that he would lose his passion if he tied himself down for several years.
He told Sport: "Every day I think that I could be leaving the day after. I work better when I know that I have the freedom to decide my own future.
"There is a risk that you lose your passion for what you do when you sign a long-term contract. It is all about passion. The biggest wealth that someone can have is doing something that you really like. That is the essence of everything in my opinion."
Barca are currently joint top of La Liga with surprise package Levante after six games, one point ahead of Real Madrid.