Jaime Alguersuari turned down the chance to be Red Bull's official reserve driver in 2012.
That is the claim of Adrian Newey, the highly rated car designer and technical boss at the energy drink company's championship-winning team.
Red Bull dropped 21-year-old Spaniard Alguersuari from its rookie team Toro Rosso after two and a half seasons, then installing his former teammate Sebastien Buemi as the 2012 reserve.
"We closed the agreement as third driver with Sebastien Buemi after Alguersuari did not want to join our team," Briton Newey is quoted by Spain's Mundo Deportivo newspaper.
The Swiss newspaper Blick quotes Alguersuari as saying this week: "I am negotiating with top teams for the role of reserve driver."
Dr Helmut Marko, the manager of Red Bull's driver programme, told Italian website 422race.com this week that Buemi was selected for the reserve role because he has "more experience of the simulator" than Alguersuari.
He denied Alguersuari was snubbed because of his videotaped row with the Spaniard after a practice session in Korea last year.
"No, not at all," said Marko. "We had an evaluation of the possibilities and we took what we thought was the best available for us."