The German, who suddenly quit Mercedes and the sport after winning the title late last November, was already in Barcelona this week for a Mercedes sponsor event.
He said there: “I might go to the track tomorrow (Wednesday) just to say hi and check it out, as I’m here anyway.”
And Rosberg later confirmed on Twitter: “(I) stayed in Barcelona to go check out the new cars at the track tomorrow. Will be fun.
“I’ll let you know what I think!”