Evaluating how long it could take the seven-time champion to make it back to the top

They're already calling it the story of a decade, and it's only just begun: Michael Schumacher is back in the Formula 1 World Championship with Mercedes Grand Prix. Mercedes, of course, is the organisation that blooded the German in sportscar racing in 1990/91 and then propelled him into F1 with Jordan.

Renewing the link-up with Mercedes team chief Ross Brawn gives Schumacher every chance of exceeding his total of seven world titles, even at the age of 41.

But how will he fare in the Castrol Rankings? We've plotted a narrow world-title-winning season for Schumacher, giving him, after 17 races, exactly the same number of world championship points as Jenson Button scored in 2009. With this year's F1 calendar set to feature 19 races, he exceeds Button's total over the final two events. We've given him five pole positions, five wins, seven other podium finishes, various lower results, a couple of non-finishes, six fastest laps, four most laps led and he finishes on the lead lap 15 times.

As the Castrol Rankings are based on a 12-month rollover period, Schumacher starts the season on zero points, behind even NASCAR Truck Series part-timers such as Brandon Duchscherer and Clay Rogers. Also, with 19 races compared to 17 in 2009, on adjustment there will be slightly fewer points available from each F1 round in 2010.

After qualifying third and finishing second in the Bahrain opener, Schumacher moves onto 1286 points. He's already ahead of those Truck boys - and hapless 2009 Ferrari stand-in Luca Badoer!

By the time the teams pack up from round eight in Canada, where Schumacher has added a third win to the victories he picked up in Australia and Turkey, he's on 11,130 points. That should put him just inside the top 30 and making up ground fast.

We're also expecting the 2009 F1 top scorers in the Castrol Rankings to lose some ground: new McLaren recruit Button is unlikely to match his stunning early-2009 form, and those high scores will be wiped out in the early months; Red Bull pairing Sebastian Vettel and Mark Webber will have a revitalised Ferrari and McLaren to contend with; and Rubens Barrichello is unlikely to fare as well with Williams as with Brawn. Conversely, Lewis Hamilton will be making an attack on the top of the Castrol Rankings table with a more-competitive McLaren as his dismal early-2009 results are erased.

Elsewhere, World Rally star Sebastien Loeb has very little scope for improvement, and IndyCar top dogs Scott Dixon, Ryan Briscoe and Dario Franchitti are likely to continue to swap honours between them. There is not much scope for these drivers' scores to change significantly, although NASCAR's Jimmie Johnson could be a threat if he makes a livelier-than-usual start to the season.

A post-Canada run of seven races without a win is frustrating for Schumacher, but don't forget that whatever happens he is gaining points as he has none to be dropped from 2009. That leaves him on 17,382 points and in the Castrol Rankings top 10 with four races to go.

Victory in Japan moves him onto the fringes of the top six, a podium in Korea lifts him into the top four. Then a dominant win from pole in Brazil moves him into the lead. A characteristic last-race wobble in Abu Dhabi means Johnson, Loeb, Hamilton, Button and Ferrari new boy Fernando Alonso get closer, but he scores just enough Castrol Rankings points to trump Button's 2009 total.

A long shot? Maybe, but more likely than Button and Brawn winning the 2009 world title would've seemed 12 months ago!