Kamui Kobayashi thinks he might still have an opportunity to remain in Formula 1 with another team despite losing his Sauber seat to Esteban Gutierrez.
The Japanese driver's lack of sponsorship was key to Sauber's decision. Kobayashi has been striving to find more funding and thinks he might now have enough backing to secure one of the remaining vacant seats.
Force India and Caterham are the main options for drivers yet to secure 2013 drives.
"We're just waiting for some money to come in," said Kobayashi.
"We're waiting, we just need a sign."
He underlined that nothing was secured yet, saying: "It will be difficult. I'm talking with another team, but it's difficult to say."
Kobayashi added: "If I don't talk [to other teams] it means I'm retired."
He said he had no hard feelings towards Sauber, despite being dropped just after securing his maiden F1 podium at Suzuka.
"I'm not disappointed. They need a sponsor and more money for the team," Kobayashi said. "I cannot find money in such a short time."
He said he was not interested in looking for a reserve driver role.
"I want to race, I don't want to walk around here as a test driver," Kobayashi insisted.
"I've already done two years as a test driver with Toyota and I know how that feels.
"It's not easy to wait around for 20 races. To stay here without driving is like being in jail."
Toyota supported the early part of Kobayashi's career and gave him his F1 break in late-2009. The Japanese manufacturer now has a successful World Endurance Championship programme, but Kobayashi insisted it was too soon to consider non-F1 options.
"It's too early to think about that. I'm not really interested in that," he said when asked if he would chase a Toyota WEC seat.
"I want to be in Formula 1. I think I can be more successful if I have a chance."
He will start 15th for his final race with Sauber in Brazil.
"I want to get a good result for the team in my last race for Sauber and I think there is a chance to do so," Kobayashi said.
"I just want to work with the team and say goodbye with a smile."