Raikkonen is returning to the sport with Renault in 2012 after a two-year absence from F1 in which he has competed in the World Rally Championship and NASCAR. Vettel and Raikkonen reportedly meet near their Swiss homes to play badminton on occasion, but Vettel warned that his friend could face the same problems Michael Schumacher has since his return to the sport last season.

"We have all seen Michael's comeback," he is quoted by France's 20minutes.fr on a visit to Red Bull's engine supplier Renault. "He [Schumacher] left when he was at the top, but when he came back he said a lot had changed and that he needed time to adapt. If I think about the car I drove two years ago, so many things have changed. It's amazing. Even during a season, new buttons appear on the steering wheel. I can imagine it would be very difficult to return straight away to the same level as before."

Renault boss Eric Boullier revealed on Tuesday that Raikkonen will soon be able to use the team's new driver simulator and get some laps under his belt in a two-year-old "demo car" before real testing begins in February.

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