Max Verstappen's father has played down the 19-year-old Dutchman's chances of winning the world championship in 2017.
Red Bull is tipped to be Mercedes' closest challenger this year as the sport's technical rules change significantly, and Verstappen has been marked out as an obvious title winner of the future.
Yet Max's father Jos, who also raced in Formula 1, thinks that it is "too early" for the championship this year.
"Of course there is talk of a world title," the 44-year-old former Benetton driver said, "but my personal opinion is that it is still a year too early."
However, Red Bull themselves are confident that Adrian Newey can ace the new aerodynamic rules, and team boss Christian Horner thinks that Renault is now ready to step up to Mercedes's level of engine performance.
"They have had a big winter," he said, referring to the French carmaker whose power units are rebranded as Tag-Heuer for Red Bull.
Jos Verstappen agrees that 2017 should be a good year for the energy drink-owned outfit.
"Last year Max won in Spain, so hopefully he can win more races this year. I would like to see three or four, and I think it's possible," he told Dutch broadcaster Ziggo Sport Totaal.
"Red Bull has always been strong with new rules, and with the information that I have, I think it looks really good."
Jos said recently that Max has been training so hard that he is "exhausted" in the evenings.
Verstappen snr adds now: "He has put on three or four kilos, mainly in muscle mass. You can see it on his neck and arms.
"He is training really hard, but he had to because the cars will be much faster, especially in the corners."
The 2017 championship begins with the Australian Grand Prix on March 26.
