Johann Zarco's KTM MotoGP career is over after just 13 races.

Having already agreed to release Zarco from the second year of his factory contract due to ongoing struggles with the RC16, KTM has now replaced the six-time premier-class podium finisher with test rider Mika Kallio for the remainder of this season.

Zarco revealed at Misano that he would not take part in a forthcoming private KTM test with the 'totally new' 2020 bike , but gave no indication that he would be missing from Aragon this weekend.

A KTM statement announcing the decision read: 'Red Bull KTM will field current test rider Mika Kallio alongside Pol Espargaro for the remainder of the 2019 MotoGP campaign... Johann and KTM decided to mutually end their association at the end of 2019 but developments and on-going work mean that priorities have been realigned. The Frenchman will be exempt from his MotoGP duties but stays contracted to KTM until the end of the season'.

"We have to make decisions to ensure that we use our resources in the best possible way and we are currently in a positive direction with our MotoGP structure," said Pit Beirer, KTM Motorsport Director. "We firmly believe that Mika can help us in this stage thanks to his knowledge and background. It is paramount that we verify our testing results in real race conditions to start our 2020 season in the best position.

"Mika has proved his ability on the RC16 and we are happy that he joins the line-up as a racer again. There is no doubt that we will focus on a new configuration with the #82 bike while fighting for points in the last races of the championship.

"At the same time we want to express gratitude to Johann for his effort since he joined our ambitious project in November last year. We now have to think of the future and are making this step accordingly. KTM will continue supporting him until the expiry of our contract at the end of the 2019 and we truly wish him all the best for his future."

Kallio rode the KTM on its MotoGP debut at Valencia 2016 and has taken a best finish of tenth (twice) during seven wild-cards for the team. The Finn is also thought to be among the main contenders for the vacant 2020 race seat, alongside Pol Espargaro.

Zarco meanwhile is aiming to secure a test and wild-card deal next year with a view to making a full-time comeback in 2021, when most MotoGP rides are up for grabs.

A return to Yamaha is seen as Zarco's best chance for a test seat, but is by no means certain.

The double Moto2 champion is 17th in the world championship, the highlight of his KTM career being the factory's first front-row start qualifying in damp conditions at Brno and a dry-race best of tenth in Catalunya.

Espargaro, who qualified second on the grid at Misano, is eleventh in the standings.

Kallio now shares KTM test riding duties with Dani Pedrosa.