Mika Kallio has confirmed that Sunday's Australian Grand Prix was his last event in MotoGP for the foreseeable future.
The Finn, who has been with Pramac Ducati since his MotoGP debut at the start of 2009, has struggled with a shoulder injury since round three at Le Mans.
Kallio will be replaced by Carlos Checa for the last two rounds of the year, although Pramac will wait before confirming their new rider.
"It is since Japan's race that the pain in my left shoulder, injured in Le Mans race, has become too intense," said Kallio. "I immediately talked to the team who understood my situation and agreed that I would try to race in Malaysia and Australia and then decide to continue or not in the last two races.
"Unfortunately, despite the good race today [11th], the pain didn't allow me to perform in the best way, and together with the Team, we decided to conclude our partnership today. It has been a hard choice for me, but in this way I'll be able to find the best physical condition and think about my future.
"I would like to thank Paolo Campinoti that was very helpful in managing this situation. I would like to also thank all the technical staff of the Pramac Racing Team with which I have found myself very well in this two years and I'll always remember them with great affection."
During his debut 2009 season in MotoGP, Kallio took a best finish of seventh - whilst substituting for Casey Stoner at the factory Ducati team - and two eighth places on the Pramac bike.
15th in the championship - as the top rookie - with 71 points, the former 125 and 250cc title contender has scored just 43 points during the first 16 races of this year, with a best of seventh once again.
Pramac team principal Paolo Campinoti made clear it had been Kallio's decision to stop.
"I would never like to find myself in these situation, but when a rider asks you to not run because he cannot give 100% for the Team, you don't think to do any more than accept his gesture of sincerity," he said.
"We had accepted his request and I would like, on behalf of the Pramac Racing Team and our partners, to thank Mika and wish him a wonderful future full of happiness and success.