Rubens Barrichello has revealed he is not sure who will be his teammate in 2011.

The veteran Brazilian had urged his British employer to also renew Nico Hulkenberg's contract, but Williams has instead cleared the second race seat for next season.

It is widely believed that the team made the decision because it needs the financial input of the new GP2 champion Pastor Maldonado, who brings substantial sponsorship from Venezuela.

But at the Granja Viana kart race in Brazil, Barrichello said: "I really don't know if he is coming or not.

"In my case, they (Williams) made my announcement (about staying in 2011) without telling me. So I don't know," he insisted.

Barrichello also commented on Red Bull's championship sweep in 2010, admitting he thought the policy of avoiding team orders altogether was a "great example" for other teams.

"There's always a lot that the people outside (the team) don't know, but I think it was cool anyway," he is quoted by Globo Esporte.

"It is the opposite of what Ferrari did in Germany," said Barrichello, who in 2002 was famously ordered to give up victory in Austria to his then Ferrari teammate Michael Schumacher.

He also commented on his recent first taste of the Pirelli tyres for 2011.

"I liked how the car adapted to the new tyres," said the 38-year-old. "They felt good. Until the first race it is impossible to say more, but so far I like it."