Red Bull faces a real challenge to retain four-time Formula 1 champion Max Verstappen, according to former driver and Sky Sports analyst Martin Brundle. 

Verstappen has been honest about his dissatisfaction with the new era of regulations, initially describing them as "Formula E on steroids". While the Dutchman is under contract with Red Bull until the end of 2028, he has revealed that he is considering walking away from the championship at the end of the current season.

"They have, because Max has made it quite clear he wanted to see how the car goes, and so any updates they bring, and the power unit has been pretty impressive actually," Brundle told Sky Sports F1 when asked if the Milton Keynes outfit had got a job on its hands to retain Verstappen.

"So, the car itself has been struggling a bit. We'll see again. Red Bull will have some big changes this weekend. So Max will want to see through the mid-season that they're on top of these regulations. They're on top of the car.

Max Verstappen, Red Bull Racing

Photo by: Alastair Staley / LAT Images via Getty Images

"I'm not sure it's that easy for Max to just jump ship at the moment. I mean, Mercedes has got two homegrown talents in their car in Russell and Antonelli, and McLaren are set there with a tremendous lineup that gels very much. Ferrari with Leclerc and Hamilton.

"If somebody springs out of one of those cars, then there's a slot for Max. But the teams can't if they're contracted, and they won't want to boot out some great drivers with a great driver line-up. If you're going to leave Red Bull, it's going to be for performance only; it was going to have to be one of those three teams I just mentioned."

The next race is the Miami Grand Prix at the Hard Rock Stadium on 1-3 May.

Photos from Miami GP - Thursday

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos

Miami GP - Thursday, in photos