Maverick Vinales has left Monster Energy Yamaha ahead of schedule, the team announced on Friday.
Vinales and Yamaha agreed earlier this season to cut short a contract that was supposed to run through 2022, with the rider instead leaving at the end of this season.
But Vinales was at the centre of controversy at the Styrian Grand Prix, where he failed to finish.
The Spaniard cited electrical issues with his bike, but Yamaha told of his "irregular operation of the motorcycle", which "could have potentially caused significant damage to the engine".
Vinales was then cut from the Austrian GP and now will not ride for the team again.
The decision was announced in a statement, with Yamaha's team managing director Lin Jarvis explaining: "In Assen, Yamaha and Vinales already announced the mutual decision to cut short their original 2021-2022 programme and to finish it at the end of 2021.
"A commitment was made by both rider and team to continue to the end of the current season, with the team guaranteeing its full support and the rider giving his maximum efforts so that we could finish the project 'in style'.
"Regretfully, at the Styrian GP, the race did not go well or end well and consequently, after deep consideration by both parties, the mutual decision was reached that it would be better for both parties if we end the partnership earlier.
"The early separation will release the rider to be free to follow his chosen future direction and will also permit the team to focus its efforts on the remaining races of the 2021 season with a replacement rider – yet to be determined."
Vinales joined Monster Energy Yamaha in 2017 after leaving Team Suzuki Ecstar, where he had one victory across his first two seasons in MotoGP.
With Yamaha, Vinales added eight more victories among 24 podiums, finishing third in the championship in 2017 and 2019.
This year, he started the year with a triumph at the Qatar GP and was second as recently as the Dutch TT, where the initial announcement with Yamaha was agreed.
Vinales is sixth in the standings at the time of his departure.