The Belgium midfielder, the key player in City's 2018 title victory, played only a bit-part in last season's treble success due to knee and muscular injuries.
De Bruyne, who scored a goal and set up another in Saturday's 3-1 win over sister club Yokohama F Marinos in Japan, said: "I'm fine. What happened last year happens to everybody. I have been a professional for 11 years now and had one season where I had some injuries.
"But by the end of the year I still played 32 games while a lot of players only do that every year. I just get on with it.
"Now I feel good. I'm happy I could play a whole pre-season. I've played four games."