James Stewart is returning to AMA Pro Motocross Championship competition this weekend at Unadilla aboard his San Manuel Yamaha. This is significant. It means the fastest motocross racer in the planet is coming back to race in the series for the first time in nearly two years. The last time Stewart raced the outdoor nationals he swept the series going undefeated in 2008.

Stewart’s return is great news for the fans, the promoter of Unadilla and the TV ratings (live on NBC this Saturday at 3 p.m. Eastern). Stewart picked a perfect reentry point. Unadilla is one of the legendary motocross circuits in the world and he is a master there. That and the fact that coming into Saturday’s national Stewart is in a classic win-win situation.

Should Stewart win it would mark one of the greatest comeback performances in motocross history. If not, no problem – it is after all only his first race back in the nationals after two years.

Stewart’s comeback is bad news for only one man and that’s Rockstar/Makita Suzuki’s Ryan Dungey. Dungey holds a seven-race win streak along with firm control of the 450 Class, so he’s going to be in no mood to get into a wheel-to-wheel battle with a rider who is not a factor in the championship. So if the racing gets heated Stewart has nothing to lose by taking a few more risks, while Dungey has a title to protect.

Yet the conundrum for Dungey is that if he can’t (or won’t) beat Stewart this weekend, in a way that invalidates his entire performance this summer. If Stewart comes back in his first outdoor national in nearly two years and defeats the rider who has dominated the nationals this year, it proves that Dungey is a mere pretender, holding the throne simply by abdication.

It’s going to be interesting. There’s no question that when he’s on his game that Stewart is the fastest rider the sport has ever seen. Yet Dungey is “match tough” as they say in tennis, having been clicking off perfect motos all summer long.

Is Stewart healthy and in shape? Does Dungey have the speed to run with Bubba?

I for one will be glued to NBC Saturday afternoon to find out the answer.