The Dutch striker joined Gladbach from FC Twente last week, but when asked by the Bild am Sonntag newspaper if he would rather win the title or the top goalscorer's award, he reacted with amazement.
"The title? Are you kidding? That would be a bit too much to ask at the moment," he said.
"The club has taken the next step forwards with the new signings, but we must keep our feet on the ground."
Gladbach finished a surprise fourth last season having only just avoided relegation to the second division in a play-off 12 months before.
They will face a play-off for a place in the Champions League next month and De Jong believes the club do have a bright long-term future.
"Maybe we can win a title over the next five years," he said. "It is no coincidence that I signed on until 2017."