Raymond Vermeulen, who looks after the interests of Max Verstappen, says the teenager is committed to Red Bull but his patience could run out if under-performance persists.
Verstappen was expecting to run at the front and challenge for victory with Red Bull Racing on a regular basis this season, but the disappointing speed of his RB13 coupled with reliability woes have led to a frustrating first half of the year.
Speculation also emerged that perhaps the Dutchman was not happy with his affairs at Red Bull, encouraging pundits to predict a move to Ferrari, a scenario quickly quashed however by both Verstappen and the Milton Keynes-based outfit.
Despite the fact that the 19-year-old's contract with Red Bull runs until the end of 2019, interest is always present, according to Vermeulen.
"Ever since Max made his debut, there was always interest," the manager told Dutch publication Formule 1.
"Other teams were ready to offer him a contract, but we want to win with Red Bull Racing," he said.
"Red Bull considers Max their star and will not sell him."
Red Bull mogul Dietrich Mateschitz recently said however that a driver cannot be forced to comply with a contract.
"We do not have any specific deadlines for Red Bull, but it is important that Max continues to achieve success," added Vermeulen.
"I'm still confident in the progress of the team, because Red Bull Racing has won four world championships together with Renault.
"But it must be understood that our patience is not unlimited," he concluded.
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