Yamaha team boss Davide Brivio has admitted that they could still switch tyre suppliers for 2008, but denied that a deal to run Valentino Rossi on Bridgestones has already been done.
Although it had appeared last month that Yamaha and Michelin would continue their relationship into next season, rumours abounded in Australia that the team would either switch to Bridgestone or source a supply of the Japanese tyres for Rossi's bike only.
Rossi heightened the speculation by confirming that he had requested Bridgestone tyres, and he then reiterated his criticism of Michelin's current performance after finishing third in the race.
The situation is further complicated by the possibility that MotoGP will introduce a control tyre for 2008, with a decision on the proposal due by this weekend's Malaysian Grand Prix. Dorna boss Carmelo Ezpeleta hinted at Phillip Island that it was now more likely that the tyre war would be allowed to continue.
Brivio said that Yamaha would not make any moves regarding their tyre choice until after the Sepang announcement, but conceded that they might evaluate an 'alternative' to Michelin once the situation was clearer.
"At the moment we haven't decided anything," he told Gazzetta dello Sport. "There is a proposal from the federation to use a single tyre next year, but a decision on the matter will only be taken next weekend.
"If it doesn't get approved, as it happens in a free market, everyone will try to get the best material available.
"We'll make some considerations, we'll talk to Michelin and we'll possibly evaluate some alternatives.
"But I absolutely deny that there is an agreement or ongoing talks at the moment."