Callum Ilott is lined up to drive Arrow McLaren's No. 6 Chevy in place of David Malukas for the Indianapolis 500 Open Test scheduled for Wednesday and Thursday, according to a source. Malukas, 22, has yet to make his debut for the team due to his recovery from Feb. 13 surgery on torn ligaments in the dislocated left wrist he suffered in a mountain biking accident. When reached, Arrow McLaren declined to confirm the news, but an official announcement is expected by Tuesday.

Immediately following surgery, Arrow McLaren said in a release that Malukas' recovery was estimated to take six weeks from the removal of his stiches Feb. 22 -- dating to last Thursday. At the Thermal Club during IndyCar's $1 Million Challenge weekend in late-March, Malukas told IndyStar, "The team is pretty adamant on me doing Long Beach, so we're doing it," and noted he'd be getting pins out of his wrist that following week. He also told the NBC broadcast that a Long Beach return would be "tight."

"It's going to be tough, but I have a lot of good people and support around me," he said.

At St. Pete in early-March, though, Malukas indicated that recovery may not be as simple as hopping back into a racecar immediately at the removal of his cast. Initially, he sported a massive one that restricted movement of nearly his entire lower left arm, including his fingers and, of course, his wrist. By St. Pete, he was back to moving his fingers while sporting a much slimmer brace, and he said he had no physical pain and was starting small tasks like opening and lifting things and conducting small exercises to keep the tiny muscles around his injury limber.

His timeline to get back in a racecar, he told IndyStar at St. Pete, was "TBD, depending on how the therapy goes."

"But I have all the support from McLaren and IndyCar to make sure we're doing everything we can to make sure it heals as quickly as possible," he said. "I can't move my wrist for six weeks to make sure it heals properly, and after that, when nothing has moved for six weeks, all those muscles are going to be stiff."

The toughest part of the whole months' long saga, Malukas said then, have been the mental and emotional strains of race weekends. The need to continue to stay involved with and learn from the Arrow McLaren personnel he'd been training with and learning from all offseason is of utmost importance to keep him prepared for whenever he does get back in the car. It's in those moments, though, that he realizes what he's missing.

"It's been a little bit tough being here and seeing everything happening, being with the engineers and everyone talking, and I'm not really involved," he told IndyStar at St. Pete. "I'm still learning a lot. This is my first time experiencing how the team handles a race weekend. There's a lot to learn.

"So I guess there are some plusses to it, but of course, nothing is going to beat being in the car."

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When that next chance will be for Malukas to get back inside the cockpit of his No. 6 Arrow McLaren Chevy is unclear. With 500 Open Test duties now passed along to Ilott, the third-year IndyCar driver is questionable to participate in the upcoming Grand Prix of Long Beach one week later. The idea that Malukas wouldn't be ready for a far lesser physical strain of making a series of left turns at the Indianapolis Motor Speedway on April 10-11, but would be able to handle the rigors of one of the bumpiest and most technical street courses on the IndyCar calendar at Long Beach seems unlikely. Immediately after Long Beach follows the race weekend at Barber Motorsports Park -- considered by many drivers to be one of the most physical circuits on the calendar.

Theo Pourchaire likely to run Long Beach, Barber

As a likely substitute for Malukas for Long Beach and Barber, Arrow McLaren has been preparing 20-year-old Frenchman Theo Pourchaire, the 2023 Formula 2 champion. Pourchaire arrived in Indianapolis late Tuesday evening last week and on Thursday was in the Chevy simulator in North Carolina alongside Arrow McLaren's one-off Indy 500 driver Kyle Larson and team sporting director Tony Kanaan, according to a source. As recent as Sunday evening, he posted a selfie from what appeared to be an Indianapolis-area hotel gym to his Instagram stories with the caption, "New challenge coming soon."

Ilott is unable to fill-in for Long Beach, having already committed to racing the 6 Hours of Imola April 21 as part of his full-season WEC campaign with Hertz Team Jota.

This season, Pourchaire is contracted to compete in Super Formula while serving as a reserve driver for the Sauber Formula 1 team. Should he tackle the Long Beach and Barber IndyCar rounds, Malukas will have missed three months of action to start his Arrow McLaren. While he was announced on a multi-year deal last September, there has been growing speculation in recent weeks as to how Arrow McLaren management may continue to navigate their future with the driver, with the belief that the pair's contract could include clauses about the number of days the driver could miss before the team would be allowed to pursue other permanent options.

At the moment, Malukas has missed nine days in the car since his accident -- three days of testing and three days each at St. Pete and Thermal. Should he be out until the Sonsio Grand Prix on the IMS road course May 11, he will miss at least eight more (two for 500 testing and three each at Long Beach and Barber).

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"It's definitely heartbreaking not to have David in the car to start the season. He's won a lot of people over on how he's coming into the team with moving down to Indianapolis and being an ever-present face in the shop and the effort he's put in," team principal Gavin Ward told IndyStar days before the season-opener at St. Pete. "These things do happen, and while we don't want them to happen and we can always second-guess, what matters is now is how you react to it.

"I've said to (David) that what's really important, first and foremost, is we only want to put you back in the car when you're ready, so we need to be really open about where we think we're at. It's okay to not be ready. Secondly, we want to get you back in the car as soon as possible, but first and foremost when you're ready."

This article originally appeared on Indianapolis Star: Callum Ilott set to sub-in for injured David Malukas at Indy 500 Open Test