Advisor Helmut Marko says there's growing concern within Red Bull that four-time champion Max Verstappen will leave the team at the end of the season, according to ESPN's Laurence Edmondson.
"The concern is great," Marko told Sky Germany after Verstappen finished sixth at Sunday's Bahrain Grand Prix, according to ESPN.
"As I said, improvements have to come in the near future so that he has a car with which he can win again. We have to create a basis with a car so that he can fight for the world championship."
Verstappen has shown frustration with his vehicle through the first four races of 2025 and said he believes Red Bull has taken a step back since last season.
Despite complications with his car, Verstappen sits third in the driver standings, just eight points behind McLaren's Lando Norris for the top position.
Verstappen is under contract with Red Bull until the end of 2028, but Marko revealed earlier this year that the 27-year-old's deal includes performance clauses that could allow him to leave before then.
Verstappen has previously been linked to potential moves to Mercedes and Aston Martin.
