MotoGP championship leader Marc Marquez says his team-mate Jorge Lorenzo "needs to" persist with his current Honda challenge, following suggestions that Lorenzo could depart after the 2019 season.
Pramac Ducati rider Jack Miller admitted in the lead-up to MotoGP's Red Bull Ring weekend that there was "some truth" to reports linking Lorenzo to a potential return to the Ducati fold next year.
The 32-year-old rider, who won three MotoGP titles with Yamaha, has struggled to gel with Honda's RC213V bike.
Lorenzo scored just 19 points in his first seven races before he was sidelined by injury.
Asked about the possibility of a premature end to Lorenzo's two-year Honda deal, Marquez said: "What I only know is that Jorge has one more year with Honda.
"Jorge is Jorge, and what he says [is] 'he's not a great rider, he's a champion'.
"And if he's a champion, he's [going to be] on a champion bike [and] he needs to come back and show his potential with a Honda bike and be on the top with a Honda bike.
"And I think with his ego and his ambition, he will try to do [this] because if not, it's something that will not arrive [at] his ambition or his dream.
"I mean, when you arrive in a project like HRC, it's because you want to win races and fight for the championships."
Ducati's Andrea Dovizioso, who had an infamously tumultuous relationship with Lorenzo during their time as team-mates, said he "completely agreed" with Marquez's view.
"I don't know about Jorge's current situation, and I don't know how to judge it. He still has a one-year contract with Honda and these rumours are peculiar," said Dovizioso.
"But it doesn't concern me. I still have a year's contract and I'm focused on myself.
"I don't think his [Lorenzo] arrival [within the Ducati fold] would influence next season. We know what we need to improve and fight Marquez. The rest counts for very little."
Lorenzo's former Yamaha team-mate Valentino Rossi said the idea of the Honda reuniting with Ducati made "some sense".
But Rossi also pointed out that Lorenzo has been unfortunate with injuries during his stint at Honda.
"I think that he can ride this bike in some way, maybe he has to modify something [in his style]," said Rossi.
"He was also very, very unlucky, especially [with] the first injury with the flat-track bike before the first test.
"That one was a disaster for him because he arrived already injured and that moment of the season is crucial - because you can have six days riding the bike without the pressure of the weekend.
"He doesn't take the test and after, when you arrive at the race weekend, everything is more difficult because you don't have time, you have to push.
"Every time he did some mistake, he crashed and he had more injuries. It's a difficult situation at this moment, but he is with [a] factory Honda and with a bit more time, a bit more luck, he can be competitive."