Nicky Hayden's quest to deliver seven strong races during the closing half of the 2008 MotoGP season has been thrown in doubt by a heel injury at the X Games.

The 2006 world champion hurt his right heel when he made a heavy landing during practice for the Supermoto event on Friday August 1. At present, Hayden can only hope that the injury won't prevent him from riding in this weekend's Czech Republic Grand Prix.

"Hopefully I'll be fit for Brno," he said. "I didn't crash, I just landed wrong. I'm not sure if my foot came off the 'peg or what, but it feels pretty fragile. I'm pretty bummed out about it because I want to get out there and finish this season strong."

Hayden, whose Repsol Honda contract looks unlikely to be renewed at the end of this season, has taken two fourth place finishes so far this year - having been denied a 'safe' third when his pneumatic-valve RCV ran out of fuel on the exit of the final at Assen.

The American currently sits eighth in the world championship standings. Repsol Honda will release further details regarding Hayden's fitness 'as soon as they are available'.

Meanwhile, should he ride, Hayden is aiming to avoid a repeat of Michelin's Laguna Seca misery by having a wide range of tyres available for the resurfaced Brno circuit, and is looking forward to exploiting the power benefits of his pneumatic RCV along the lengthy uphill straights.

"I can't wait to try out the new surface at Brno," he said. "The last couple of years the surface has gotten quite old, not really bumpy but just so abrasive and cracked, so I think with a brand new surface the track is going to be awesome.

"I heard they didn't just reseal it, or just put something on top, they did it the right way and started over. That's going to be crucial for tyre wear, so we'll probably have a bigger range of tyres than we normally do, both front and rear, to make sure we've got something," Nicky confirmed.

"Brno is quite fast and open. It'll be the first time we've taken this new bike - with the pneumatic valves - to any place where we can really stretch its legs and see what she's really got," he declared.

Hayden's team-mate Dani Pedrosa, who missed the previous US Grand Prix due to injury, will return to action this weekend.