The Spaniard joined Gresini Racing in October, ending an 11-year association with Honda, who have struggled to keep up with Ducati's bikes in recent seasons.
The Italian manufacturer dominated MotoGP last year and while Marquez said expectations were "super high" he was mindful of his struggles over the last four years.
"I don't pretend I can win from the beginning because it would be a huge mistake," he told reporters on Thursday ahead of the season-opening Qatar Grand Prix.
"I arrive in a manufacturer where there are two-three guys that are riding this bike super fast, super good. I need to learn from them.
"We also cannot forget that every athlete has his moment and then starts to drop. Then you need to work harder and harder to avoid that drop."
Marquez won his last title in 2019 before his career was derailed by an injury in the season-opening race of 2020, which ruled him out for the rest of that year.
He has struggled since returning, his last race win coming in October 2021.
Asked if his performances had declined, Marquez said: "I will understand this year. Last year, I was suffering but, I was still the first Honda rider.
"During seven years I won six championships and one year was third. 2020 changed my life. Since then, it's been a nightmare. Now I intend to answer many questions to myself.
"I don't need to answer all the questions in the first race. What I want to do is feel competitive again. That doesn't mean winning the championship, it means fighting for the top five or six positions."
