The four-time world champion has found it difficult to match the pace of McLaren, Ferrari and Mercedes this season.
After the opening 11 races, Verstappen is still searching for his first grand prix victory of the campaign, although he has secured five podium finishes.
Last season, Red Bull recovered from a difficult spell with a major car development programme that helped Verstappen fight back into title contention. However, Marko does not expect history to repeat itself.
“They aren’t consistently fast. Moreover, things don’t seem to be going entirely smoothly between Max and the engineers,” Marko told *Krone*.
“The competition from McLaren and Ferrari is too strong, and the car is too unstable. I certainly wouldn’t bet on that.”
Red Bull’s lack of consistent performance has allowed its biggest rivals to share the race wins this season, with McLaren, Ferrari and Mercedes all standing on the top step of the podium.
Despite the difficult campaign, Verstappen’s future remains one of the biggest talking points in the paddock. Although he is contracted to Red Bull until the end of the 2028 season, reports linking him with a move elsewhere continue to surface.
Marko, who has played a key role in Verstappen’s career at Red Bull, made it clear he wants the Dutch driver to remain with the team.
“I sincerely hope he stays,” Marko said.
Formula 1 returns with the Dutch Grand Prix at Circuit Zandvoort, which takes place from 21 to 23 August, where Verstappen will hope to give his home fans something to celebrate.
