Yamaha MotoGP team boss Davide Brivio has suggested that Valentino Rossi's strong performance in his Ferrari test this week could reawaken his interest in switching to Formula 1.
Rossi has repeatedly insisted that he has now missed his chance to join the F1 fray and that his occasional tests for Ferrari are only for his own entertainment.
But after Rossi lapped close to current F1 pace in a 2008 Ferrari fitted with GP2 slicks on Thursday, Brivio said he fears the seven-time MotoGP champion will start pondering his future again.
"I have to be worried about these excellent times because Valentino really could get the desire to change sport," Brivio was quoted as saying by Gazzetta dello Sport.
Rossi's Yamaha contract expires this season, and he has been linked with a switch to Ducati after voicing concerns about how long Yamaha could continue giving him and team-mate Jorge Lorenzo equal status.
But Brivio reckons Ducati is no longer Rossi's most likely alternative if he leaves Yamaha.
"The greatest danger is Ferrari," Brivio said.
Ferrari team boss Stefano Domenicali has said that Rossi would be an ideal candidate should F1 rules change and allow teams to run third cars.