The Italian team failed to win a race in 2011 - its first season with Rossi on board - and although its latest bike showed encouraging form in the first pre-season test, Ducati subsequently lost ground and heads for this weekend's Qatar season-opener trailing Honda and Yamaha.
"I'm a realist, and I know well that our times are still a long way off and that there are still some things to fix," said Rossi.
"We won't be able to address some of them right away, but it's also true that both we at the track and the guys back home now have a direction to work in, and we must try to do as well as we can.
"We won't completely redo the bike during the season, but we'll try to progress little by little."
Rossi said that while Ducati had lost its way at one point during the winter, it was now in slightly better shape.
"We worked hard over the winter, and although we went the wrong direction at one point, we once again managed to find the good feeling with the GP12 that we'd had in the first test," he said. "With those settings, which we'll start with in Qatar, I was able to get good feedback from the bike."
Team boss Vito Guareshi added that because Ducati was taking a dramatically different direction with its bike this year, it had to accept ups and downs during the recovery process.
"It was an off-season marked by hard work, with a lot of effort expended by Ducati and all the guys in the racing department," he said.
"Valentino and Nicky [Hayden] also had to work hard on the track, and despite some difficult moments during the winter, which I think is normal when you work on this kind of a schedule, we come to Qatar with a decent base.
"It's a starting point, or rather one of the steps along the path that we're following. We know that other steps await and we've planned for them, and as always, the races will give us more accurate answers than the tests.
"Although our priority will be to work toward putting Vale and Nicky in the best condition possible for Sunday, I'm sure that we'll also gather important information to help us continue improving our bike."