"It looks very unlikely unless things dramatically change," Karthikeyan, who had a disappointing run as a rookie this year, told Reuters on Wednesday.
"We're looking at a test driver's slot for the year 2006, build up on that and see what happens," he added.
The 28-year-old driver was signed up for the 2005 season by the British-based Jordan team which was taken over in mid-season by Russian-born Canadian billionaire Alex Shnaider and renamed Midland.
"I will be in Formula One in one way or other," he said. "Maybe in 2006 you won't see me driving, but for my long-term future a test driver's role with a bigger team is more important."
Karthikeyan raised millions of dollars in sponsorship to secure the Jordan drive but said it would be tough to find huge sums even if he was offered another drive with Midland because the car was not very competitive.