Ducati MotoGP test rider Michele Pirro will skip next week's Jerez post-season test as he undergoes surgery on his injured shoulder.
Pirro joined factory Ducati pair Andrea Dovizioso and Danilo Petrucci for this week's Valencia test, but only completed a limited number of laps on both days and ended the final test down in 19th on the timesheets.
He was due to take part in next week's Jerez test, but has decided to move forward the operation on his shoulder to next Wednesday to give himself more time in the off-season to recuperate.
Pirro's injury is a legacy of his huge Mugello crash during the first of four race outings in MotoGP this year.
He made further wildcard appearances at Misano and Valencia, and also stood in for an injured Jorge Lorenzo at Sepang, picking up a best finish of fourth in the season finale.
"We can't put it off any longer," Pirro wrote on his Facebook page.
"It has been a difficult year, maybe the most difficult of my career.
"At the end of Sunday's race I was in pain, and in the test on Tuesday I felt very tired.
"I spoke about it with the team and with [Ducati technical boss] Gigi Dall'Igna and together we decided it was best to bring forward the operation to Wednesday 28 November.
"This will give me more time to rehabilitate and return to form in time for next season.
"I expect a difficult period, but I am sure I will make it and return even stronger than before!"
As well as his test duties for the Ducati MotoGP team, Pirro has been busy this season aiding development of the firm's new Panigale V4 R race bike, which will compete in the World Superbike Championship next year.
He also picked up a third Italian Superbike title racing for the Barni squad, adding to his 2015 and '17 successes.