Cape Town - Robert Kubica will not be racing for Toro Rosso next season with Christian Horner labelling the rumours as "wide of the mark."
Last month Kubica's most likely door back into Formula 1 was closed when Renault opted to sign Carlos Sainz as Nico Hulkenberg's 2018 team-mate.
This has left few options available to the Polish drivers with reports linking him to both Toro Rosso and Williams.
Horner, though, has poured cold water on the Toro Rosso rumours, saying Williams is Kubica's "most likely" destination should he return to the sport next season.
"We did a test out of our simulator for Renault," the Red Bull team boss told Sky F1. "But I think that's wide of the mark.
"I think Williams are probably the most likely candidate for Robert and I really hope that happens for him because what we saw from testing in Hungary was pretty impressive.
"The determination that lad has shown to get back in the car, I think it would be great for Formula 1 to see him back on the grid."