Marco Melandri has left the Aprilia MotoGP team and will not compete in this weekend's German Grand Prix.
The Italian squad said Melandri and the team had reached an agreement by mutual consent to end the rider's contract with immediate effect.
Melandri returned to MotoGP this year after four years in Superbikes, but the 32-year-old has endured a torrid season.
The MotoGP race winner had qualified at the back of the field in all races and had a best result of 18th position in France.
Teammate Alvaro Bautista has been much quicker than Melandri all season and has scored 11 points for the team.
Aprilia has not yet announced who will replace Melandri in the team's line-up.