Fabio Quartararo believes Yamaha 'has to keep' Jack Miller to help develop their V4 engine throughout the 2026 season.

With Yamaha developing a V4 engine, Fabio Quartararo has stressed the importance of Jack Miller's experience, as Yamaha is still undecided on the Australian's future.

Although no official announcement has been made by Yamaha, it appears that Miller will remain in the Prima Pramac Yamaha Racing squad for the 2026 MotoGP season.

Miller is the second-best Yamaha rider in the 2025 MotoGP World Championship, only bested by Yamaha's 2021 MotoGP World Champion, Fabio Quartararo.

But his experience with V4 engines at Honda, Ducati and KTM could be vital to Yamaha's new V4 project, according to Quartararo.

"I don't know what is [the decision] with Pramac, but I think it's great to keep Jack, because he's the one who has much more experience with the V4," Quartararo said in Hungary.

"I mean, I never rode a V4. Alex [Rins, Quartararo's team-mate] rode a Honda for half a year, then got injured. Toprak never rode a MotoGP bike.

"So you have to keep one guy that has experience with a V4, I think."

Yamaha is set to debut the V4 engine at Misano in September, as their Test Rider, Augusto Fernandez, will wildcard with the new engine installed in his M1.

Quartararo will then be given to test the new V4 engine himself on the Monday during the post-race test at Misano.

Although Yamaha currently states that they have not decided if they will use the V4 engine during the 2026 MotoGP season, Quartararo believes the Japanese manufacturer has already switched its focus from the Inline Four engine to the V4.

“They have to focus on one thing. Because I think it's already difficult to make one thing well,” he said.

“So I hope they are fully focused on the V4, because we have no new things to come with the four Inline.”