The Dutchman joined after an impressive debut race with Williams at Monza last season. However, he has found Formula 1 to be a steep learning curve and has yet to score a point since that day in Italy.
Red Bull adviser Helmut Marko, who oversees their young driver programme, has threatened De Vries with the axe on several occasions in recent weeks. And, as first reported by Dutch media, he now appears to have followed through.
The Aussie racer has been a reserve driver for Red Bull this season. In that role, he has been responsibly for putting the hours in on the team's simulator to help develop their car while also taking part in extensive marketing duties.
Ricciardo hoped for a return to the grid in 2024 and had previously indicated that he did not want to step in mid-season. But Mirror Sport understands he has now accepted that role until the end of the current campaign, giving the 34-year-old 12 races to prove he remains worthy of an F1 seat.
On Tuesday, he drove an F1 car for the first time since the end of last season when he took Red Bull's RB19 for a spin around Silverstone. That was for an official tyre test, but team principal Christian Horner framed it as though it was a potential audition.
He said after the British Grand Prix: "I think it would have been a loss to the sport for him just to disappear and I think that I didn't recognise the Daniel of the last couple of years, so I'll be very interested to see what kind of job he does on Tuesday.
"It's an important test for Pirelli but it's also going to be great to see him back in a Red Bull car and seeing where he's at – both on pace and mentally, physically and to get his feedback on this car as well."
However, Horner made it clear that he does not foresee Ricciardo working his way back up to drive for Red Bull Racing again. "It's not something that we're planning, that's for certain," he said when asked if that was a possibility.