Ducati believes a planned new engine is the only hope to keep Valentino Rossi

Guareschi said he wants to retain Rossi for the 2013 season, but admitted time was running out to convince the Italian to stay.

He also said Ducati's new engine was evidence it had not stopped moving forward - something Rossi implied prior to the Dutch TT - but admitted that it has been difficult to accelerate the rate of development given existing deals with suppliers.

"We have never stopped, as demonstrated by the fact that we are working on a reviewed engine that should be ready for Laguna Seca," Guareschi told Gazzetta dello Sport.

"We do our development programs at the beginning of the year, but to accelerate is difficult, because we design in-house, but production is done together with suppliers, over whom we have little chance of intervention.

"Let's hope the engine works, because that's our only hope to convince Valentino to stay. We'd like to keep both him and Nicky, but there isn't much time, because usually the market deals close at Brno."

His comments come in the wake of renewed criticism of Ducati's current situation from Rossi, who said he could see "no solutions" in the team's immediate future.

Rossi, who finished 1.3s down on Casey Stoner in qualifying at Assen even before a rear tyre issue curtailed his race, said the fact Honda brought a new chassis to Holland highlighted the development problems at Ducati.

"Honda, who are already quick so in theory are less in need than we are, have nevertheless brought a new chassis because they believe a lot more work is needed, because they always want to improve," he told Italia1.

"At Ducati, instead, there is no such plan. An engine with different characteristics is forthcoming, but as far as the real problem is concerned, which I've already explained months ago, I see no solutions on the horizon.

"It's not a matter of time, there simply are no ideas to solve the situation. Obviously what we riders say is not taken into consideration.

"I repeat: there's no plan."

While Rossi was cagey on whether top management should be blamed, Guareschi vigorously defended the role of Ducati Corse head Filippo Preziosi.

"Is Preziosi under discussion? Filippo is everything for Ducati and I sincerely struggle to imagine a situation without him at Borgo Panigale."