Former world champion Niki Lauda does not believe Michael Schumacher will make a full-time return to Formula One with Mercedes next season.
Speculation has linked retired seven-time champion Schumacher with a return to the sport he once dominated following the German manufacturer's takeover of reigning constructors' champions Brawn GP earlier this month.
Mercedes' bosses in Stuttgart are thought to favour an all-German driver line-up for next season, following the departures of Rubens Barrichello to Williams and world champion Jenson Button to McLaren.
Nico Rosberg has been confirmed as one of Mercedes' drivers for next season, and both Schumacher and fellow German Nick Heidfeld have been linked with the other seat.
Schumacher, who retired at the end of 2006, almost returned to the sport last season as understudy to the injured Felipe Massa but was forced to abandon his comeback due to a neck injury, but Lauda does not expect to see the 40-year-old on the grid in 2010.
Reflecting on the rumours, Lauda told the official Formula One website, www.formula1.com: "I don't believe that there is one single grain of truth in them, at least from all the signals that I get.
"There was a window of opportunity after Felipe's accident and had Michael been fit he would have taken up that chance to race for three or four races - to prove himself, get the adrenaline rush, and see where he stood in the pecking order.
"But I cannot believe that he would be up for a full season. Why then he did stop racing in the first place?"
Lauda, the world champion in 1975, 1977 and 1984, praised Mercedes for its decision to enter F1 as a full manufacturer entry but warned its driver selection could make-or-break its maiden campaign.
"The takeover of Brawn GP was a masterly achievement. Now it is important to proceed in this same manner by having a very close look at the important issue of the driver line-up," he continued.
"With the Button departure, Rosberg is at the moment their only driver - a good man for sure, but good men get even better with a team-mate that gives them a hard time 24 hours a day.
"That is positive, performance and development-wise. They have to be very careful now in their selection, trying to get a top man for the second cockpit."