Ducati's winter gains too small - Rossi

The former champion has been suffering with a shoulder problem since a motocross crash almost a year ago, and had surgery during the off-season.

But he is still not back to full fitness, and thinks Ducati could have started the season in better shape had he been able to cover more miles and ride at his full potential over the winter.

"It's a difficult moment because we have to fix different problems - the first is me, and I need some more time to come back on top, or at 100 per cent, because the shoulder still gives me a lot of pain and I don't have enough power for the second half of the race," said Rossi. "I lose the power in braking and changing direction especially.

"Also we have to work on the bike and try to fix some problems. During the tests I was in a worse condition compared to now, so we did some work, but not enough."

Rossi also believes that Honda and Yamaha made a lot more progress than Ducati with their 2011 designs.

"The other manufacturers, especially Honda, did a great job and made a big step," he said. "Our bike is more or less the bike of last year and we need to do the same step."

But he denied that Ducati's current situation was the biggest challenge of his career so far.

"I don't know. The beginning with Yamaha was also a great challenge," Rossi said. "Now for sure it's a bit more difficult because the level is so high."