Sauber will name its second driver for 2013 at this weekend's Brazilian Grand Prix.
After weeks of speculation about who will join Nico Hulkenberg for next season, the outfit is set to end the long wait for main contenders Esteban Gutierrez and Kamui Kobayashi over who has got the nod.
Sauber team principal Monisha Kaltenborn refused to elaborate on the identity of the driver, or indeed when the announcement will be made.
"We have always said it will be 'in the season'," she told AUTOSPORT. "So it will be before Brazil, in Brazil or a few hours after the race."
Gutierrez has been favourite for the seat for several weeks, thanks to his close links with team sponsor Telmex, but Kobayashi has been more confident in recent days about his prospects for next year.
Speaking in Austin last weekend he said: "I'm confident. There's no change but I think it will be OK.
"I think the situation is better than before...money-wise and everything, I think it's getting better. But we'll see."