Will Michael Schumacher come back in 2010? Once again Formula One is speculating about its most successful driver and the possibility that he might be tempted into a return to the cockpit with Mercedes Grand Prix, formerly Brawn GP.

Jenson Button’s puzzling decision to leave that team and head for McLaren has led to rumours that Schumacher might be a target for Mercedes, as the team scouts around for a big name driver to join its new signing Nico Rosberg.

Such a strategy would seem to fit both Schumacher and Mercedes. It would mean a chance for the greatest German driver to team up with a German manufacturer that has always wanted his services; it would give Schumacher an opportunity to rekindle his stunningly successful relationship with Ross Brawn, the team principal with whom he worked at Benetton and Ferrari, and it could offer the seven-times world champion a competitive car to restart his career.

So far Mercedes have refused to comment on speculation that they have already approached the German legend who is in Las Vegas at present preparing for a karting event. But when asked about it this week Nick Fry, the Mercedes chief executive, would only say that there were still plenty of top-class drivers available and the team was not leaving any stone unturned in its search for a replacement for Button.

However Schumacher’s spokeswoman, Sabine Kehm, was sceptical on Friday that he might consider a full-time comeback. She said she was sure no negotiations were in progress. She pointed out that Schumacher’s decision to replace Felipe Massa at Ferrari for the final races of this year after the Brazilian was injured, was a special case. Although that comeback was thwarted by a neck injury, it would have involved only a few races and not a full championship campaign.

“The whole story with Mercedes is a beautiful one with so many things fitting together with Michael and Ross, but it is a full season next year and there are no negotiations going on,” Kehm said. Although Schumacher’s injury, which was caused when he crashed a motorbike this year, is thought to be on the mend, he will be 41 at the start of next season and he said recently he did not fancy coming back to Formula One and being seen as the old man of the sport.

While a gamble on Schumacher may or may not be on Ross Brawn’s wish list, he is also known to be in talks with Kimi Raikkonen, the ex-Ferrari driver and Nick Heidfeld, the German driver formerly at BMW Sauber. Brawn is likely to be keeping an eye on Robert Kubica, Heidfeld’s former team-mate, who has signed for Renault. If the French car manufacturer pulls out of Formula One, Kubica could be a great choice to partner Rosberg.