Who does drive in the 500 is yet to be confirmed, although Callum Ilott had been included in the media guide for this weekend’s Indy Grand Prix as the driver of the #6 Chevrolet of which Pourchaire will instead take the wheel again.

They have each started two events so far as fill-in for David Malukas, who injured himself in an off-season mountain biking accident and has now had his contract terminated.

Ilott is free of World Endurance Championship commitments for the Indy 500 and has competitive oval experience, while Pourchaire enjoyed his first taste in a test at Gateway earlier this week.

Team Principal Gavin Ward said, “We’re excited to continue working with Theo.

“He proved to be a quick learner, and we believe his skillset and learning mindset will support his development as he gets more comfortable racing in the NTT IndyCar Series.

“Now, it’s about continuing to grow and turning those learnings into results alongside the #6 team.”

The 2023 Formula 2 champion and Sauber Formula 1 reserve said, “The NTT IndyCar Series has some of the best racing in motorsport, and now I can say that with experience.

“I’m excited to take on this challenge with Arrow McLaren for the rest of the season.

“This is a special opportunity, and I am committed to learning and improving as we get on track each race weekend.

“I’ve enjoyed my first two races with the team, and I know we have plenty of potential in front of us.

“Of course, I would like to thank Zak [Brown, McLaren Racing CEO], Gavin and Tony [Kanaan, Sporting Director], as well as the Sauber F1 Team, for making this all possible.”

Practice and Qualifying on the Indianapolis Motor Speedway road course takes place tomorrow.