Daniel Ricciardo is set to return to Red Bull as the team's third and reserve driver for the 2023 season, ESPN can confirm.
ESPN understands the deal will be confirmed on Sunday, bringing the Australian back to the team he left at the end of 2018.
Ricciardo's role is expected to include simulator work, commercial obligations, demonstration car runs and being a backup should Max Verstappen and Sergio Perez be unable to compete at certain races next year.
On Friday, Red Bull's Helmut Marko told Sky Germany: "Ricciardo will be our third driver. We have so many sponsors, we have to do show runs and the like, so of course he's one of the most high-profile and best-suited."
Christian Horner told reporters on Saturday ahead of the season's final qualifying session at Yas Marina circuit, Ricciardo's contract does not include the provision of returning to Red Bull as a full-time driver for the foreseeable future.
"Daniel's contract's very specific for a specific reason," Horner said. "We have a contract with Checo [Perez] for the next two years.
"What the partnership of Max and Checo has produced has been phenomenal for us. The two drivers, they do gave a good relationship, they race well for the team and we've got no reason to see that being any different tomorrow or for the duration of their contractual commitment to the team thereafter.
"Daniel's a big character," Horner added. "It's been disappointing to see his performance this year. He's still one of the biggest names, one of the biggest characters in Formula One."
Meanwhile, there has been speculation that Red Bull junior Liam Lawson will be reserve driver next season, but it remains unclear whether he will share that role with Ricciardo. Full details will be revealed on Sunday.
Ricciardo was left without a 2023 race seat after McLaren cut his three-year contract short one season early, with the Australian failing to meet expectations.
A return to Alpine did not materialise, and Ricciardo had no interest in racing with Haas or Williams next year.
He has vowed to come back to racing in 2024 "with a vengeance".
Although Ricciardo's return to Red Bull might be seen as a sign that Perez is under pressure, the Mexican driver is under contract until the end of the 2024 season.
Information from Reuters contributed to this report.