Lucas di Grassi believes money was the defining factor in Virgin's decision to replace him in 2011.

After a single season in F1, the 26-year-old lost his race seat to Belgian Jerome d'Ambrosio, who, with the help of his management company, put together a sponsorship package to pay for his drive.

"It's a shame that Formula One seats have been for sale," di Grassi told Sao Paulo's Jovem Pan FM. "The team said to me numerous times that if the decision was made on purely technical grounds, I would be staying. But money spoke louder."

Di Grassi, a multiple race winner in GP2, said he still plans to return to F1 as soon as possible.

"This year will be a difficult one of transition and restructuring of my career, aimed at returning to F1 as soon as possible," he added.