The Sonoma event falls the weekend before the Repco Supercars Championship resumes in Hidden Valley, on June 14-16.
Waters has already made two NASCAR starts this year, in the Truck Series, in gaps between the Albert Park, Taupo, and Wanneroo events.
However, Speedcafe understands that the Tickford Racing driver’s deal also had him racing in Cup at Watkins Glen, on the weekend of Sunday, September 15.
That was, until Supercars was forced to move the Sandown 500 forward a week from the September 20-22 date on its originally published calendar.
Waters himself did not confirm the deal per se although he made comments consistent with such an arrangement when asked why he had chosen to make his Cup debut at Sonoma.
“It was pretty well the one that didn’t clash,” he told RFK Racing’s Backstretch Banter podcast.
“We have 12 [Supercars] rounds a year and pretty well all the road courses clash except Sonoma.
“I was pretty keen to do Watkins Glen as well but they moved the Sandown 500 weekend to the Watkins Glen weekend so that one we can’t do either.
“Then, obviously, the Truck stuff was just what could line up through the season as well.”
There are four road courses on the NASCAR Cup Series calendar, with the Circuit of The Americas having clashed with Albert Park and the Charlotte ‘roval’ race to be held on the same weekend as the Bathurst 1000.
Furthermore, the Chicago street race in which Shane van Gisbergen sensationally won on his NASCAR debut in 2023 this year clashes with the NTI Townsville 500 rather than falling a week prior, while the Indianapolis race where he was joined by Brodie Kostecki has reverted from roval to Brickyard 400.
It means that, aside from the possibility of more Trucks for Waters, this weekend is likely to be the last of the year in which Supercars drivers will make NASCAR cameos.
Waters will contest the Sonoma Cup race in an RFK Ford while Will Brown makes his NASCAR debut in a Richard Childress Racing Chevrolet.
Van Gisbergen, Brown’s predecessor at Triple Eight Race Engineering, will arrive at the Californian venue as the last-start Xfinity Series race winner, having driven a Kaulig Racing Chevrolet to victory at Portland.