Haug refuses to rule out Schumacher

Team boss Ross Brawn told German newspaper Bild over the weekend that rumours of a possible return by the seven-time champion were a "fantasy of the media".

"Michael would have come back temporarily for Ferrari but he doesn't want to begin a new career," Brawn added.

"I think that we have to live with these speculations," said Haug during a press conference. "What Ross pointed out, I think we have to respect that. I fully understand that these speculations are ongoing as long as we don't announce who is driving the other car but that's what we have to live with."

When asked to categorically deny Schumacher could drive the car, Haug added: "When will you ever say categorically anything in F1? Ross made it quite clear and I really have nothing to add."

Mercedes GP chief executive Nick Fry was also unwilling to discuss the Schumacher rumours.

"I've got nothing to add to that," he said. "We are here today to talk about Nico Rosberg and we should stick with that subject. Ross has answered the question extremely well."

Fry said Mercedes was in no great hurry to finalise who would partner Rosberg in its 2010 line-up, but that the decision was likely within the next month.

"It obviously would have been ideal to announce them together but that's impossible," he said.

"We don't have huge time pressure at the moment, but once one goes beyond Christmas and into the new year it becomes slightly more difficult with seat fits in time for the engineers to talk to the driver. I would hope on the other driver to do it before Christmas purely for logistical reasons."