By the time Rossi makes his first start for McLaren SP, Busch will have done so for Richard Childress Racing, and the two-time Cup Series champion says his contract allows him to do the Indianapolis-Charlotte ‘double'.
Brown confirmed that “A fourth car at the 500 is very much under consideration” and that Busch is a candidate, but indicated that his chances are somewhat unlikely.
“I have not personally spoken with Kyle Busch, but you can read into that that someone else in our organisation has,” said the McLaren Racing CEO in comments reported by NBC.
“We want to make sure if we run a fourth car, we're in the mindset that we want someone that is experienced around the 500.
“It's such an important race, and from a going for the championship point of view, we've got three drivers that we want to have finish as strong as possible, so if we ran a fourth car, we'd want to be additive, not only for the fourth car itself, but to the three cars.
“So, bringing in someone who's not done it before potentially doesn't add that value from an experience point of view.”
That is certainly not inconsistent with recent history, given the Papaya squad fielded two-time Indy 500 winner Juan Pablo Montoya in its third car for the May Indianapolis races in 2021 and 2022.
On Busch, Brown said, “[It is] not because of him but purely because of experience.
“He's an awesome talent and would be huge, huge news for the Speedway.
“I think everyone is under consideration if we decide to do it, but experience is right at the top of the list as far as what's going to be the most important to us.”
Busch is not the only NASCAR champion eyeing off the double, with Jimmie Johnson “seriously considering” the idea.
Johnson is now in semi-retirement after contesting the full 2022 IndyCar Series with Chip Ganassi Racing, although there is no confirmation yet on exactly what his 2023 motorsport programme looks like.
Meanwhile, McLaren SP has announced its new structure following the departure of Taylor Kiel, with Gavin Ward moved into the position of Racing Director and new arrival Brian Barnhart appointed General Manager.