Heikki Kovalainen has insisted that he still retains hopes of securing a seat in Formula 1 for next season.
The 32-year-old filled in at Lotus for Kimi Raikkonen, who missed the final two races of the last campaign due to back problems, but he is yet to agree a deal despite negotiations for a return to Caterham.
"I have been maintaining my training programme for Formula 1 as much as possible," Kovalainen told MTV3. "I will have a normal F1 driver's winter. The only difference to previous years is that I do not currently have a contract for next season.
"The most serious negotiations are with Caterham. But all the different factors need to come together. In any case, it should be clarified by the end of January, when the tests begin. But I am not going to end my career."
Kovalainen raced for Caterham in the 2012 season.