Six-time MotoGP world champion Marc Marquez has undergone a third operation on his right arm in Madrid and likely faces a six-month recovery period.
The Honda rider broke his right arm in a heavy crash during the season-opening Spanish Grand Prix at Jerez on 19 July.
Marquez had an operation immediately afterwards to have metalwork inserted to fix the bone and attempted a comeback just days later at Jerez for the Andalusian GP.
But he had to abort this, with the energy exerted on his arm ultimately leading to the metal plate breaking and requiring a second operation.
With recovery from this being slower than expected, Marquez never raced again in 2020, with Honda test rider Stefan Bradl deputising in his absence.
Reports in the Spanish press last month suggested Marquez would need a third operation owing to the healing process taking longer than hoped, with Marquez consulting numerous surgeons in recent weeks to determine the best course of action.
Marquez went to Madrid on Thursday for further consultation, with Spain's Antena 3 first reporting the Spaniard had an 11-hour operation on his arm.
Autosport can confirm the surgery did take place, with Honda's own statement issued late on Thursday night noting the "uneventful" operation took eight hours.
The surgery involved bone being taken from his hip, which is high in red blood cells, and grafted onto the humerus area on his right arm where a new plate was also inserted.
Marquez's recovery is expected to take up to six months, which will rule him out of the start of the 2021 season - due to begin on 28 March with the Qatar Grand Prix.
Honda has yet to comment on recovery time.
The full statement from Honda read: "Marc Marquez has undergone a new operation on his right arm as a result of the slow healing of the humerus bone, which has not improved with specific shock wave treatment.
"Today the rider has undergone surgery at the Hospital Ruber Internacional, in Madrid, for a pseudarthrosis of the right humerus.
"The surgery, carried out by a team made up of doctors Samuel Antuna, Ignacio Roger de Ona, Juan de Miguel, Aitor Ibarzabal and Andrea Garcia Villanueva, consisted of the removal of the previous plate and the placement of a new plate with the addition of an iliac crest bone graft with a corticoperiosteal free flap.
"The surgical procedure lasted for eight hours and was uneventful."
Should Marquez be unable to race for part of 2021, this leaves the door open for Andrea Dovizioso to make a surprise return to MotoGP action.
Dovizioso opted to take a sabbatical after quitting Ducati at the end of the 2020 season, with no test rider roles offered to him for 2021, which gave him a clear path back onto the MotoGP grid for 2022.
Free of any ties to teams in MotoGP, Honda could reasonably call on Dovizioso to fill in for Marquez should the Spaniard have to miss more races.
Dovizioso made his MotoGP debut in 2008 on the JiR Honda, before moving to the factory squad, with whom he raced from 2009 to the end of 2011 - scoring his first MotoGP victory with the marque at Donington Park in 2009.