The Honda rider has been absent since fracturing his hand in the controversial collision with Miguel Oliveira in the first grand prix of the season in Portugal that has led to a long-running appeal process to have a double long lap penalty overturned.
Marquez underwent surgery at the Clinica Ruber Internacional in Madrid immediately after the Portuguese GP, where he was operated on by Dr. Roger de Ona's team.
Once he was confirmed to be out of the race for Argentina, both he and his entourage were fully aware that it was almost equally unfeasible to consider riding in Austin due to the time it would take him to recover from the injury he had suffered.
Marquez had hoped to return for this weekend's Spanish GP, but an MRI that the Spaniard underwent on Tuesday advised against this possibility due to the possible consequences it could have - the Honda rider admitting on Thursday at Jerez that further damage to his thumb could have ended his career.
Speaking exclusively to Autosport, Roger de Ona, head of hand reconstruction and microsurgery at Ruber Internacional, recognises that going out on the track in Jerez would have entailed an unacceptable risk.
"Marc's fracture is known as Bennett's fracture, and it is different from a diaphyseal fracture, which we could have solved with screws and a plate," said the surgeon, who - as soon as he saw the results of the radiological tests performed on Marquez on Tuesday - was very clear about what he was going to recommend.
"In his case, there was a very small bone fragment that remained in place, while the rest of the thumb was displaced.
"That's why we need the bone to consolidate well, because in that area many of the forces generated by a MotoGP bike are concentrated.
"For an athlete who uses that area a lot, such as a quarterback, a basketball player or a driver, the recovery time ranges from six to eight weeks.
"For Marc to be able to run only four weeks later would have been exceptional.
"We couldn't take the risk of it breaking at the end of the straight at 350km/h and not being able to brake."
He added: "If the surgery were to pull out the pieces of bone, those pieces could no longer be reattached in the most appropriate way, so the chances of carrying over sequelae would be much greater.
"And, to top it off, the recovery could take several months. It wasn't worth taking that risk.
"At Le Mans, Marc will be seven weeks since the operation. In the same way we would have had to see something exceptional [in Tuesday's tests] for him to race in Jerez, we are confident that he will be able to do so in France.
"If he follows the normal evolution, seeing how things are going, he should be ready."
Dr. Roger de Ona said he is convinced that, once the bone is consolidated, Marquez will not have any sequelae.
