France's miracle man Jelonch gets chance he thought had gone
But on Thursday, the 27-year-old will lead the host nation against Uruguay in their second game of the tournament, less than seven months after suffering the sort of injury which can normally rule out a player for up to a year.
Back-rower Jelonch underwent an operation in March before spending time across France, from Montpellier on the Mediterranean coast to Capbreton on the Atlantic, in a race against time even to be in with a shout of head coach Fabien Galthie's squad.
"We felt quite quickly that he would be back with us soon," Galthie said.
"We had little signs, even if he wasn't running.
"His knee wasn't swelling. He was in the countryside, he was swimming slowly and had crutches.
"There were strong signals that he would be here," he added.
Jelonch grew up in the rural Gers department of southwest France and spent time with his local club Vic-Fezensac, then Auch, before moving to Castres before joining the giants of French rugby, Toulouse.
"I'm from an environment where mental strength has had a lot of importance ever since I was young," Jelonch said.
"I'm from the countryside, it helps too."
But the burning ambition of playing in the World Cup was the key motivation, he admitted.
"The objective in my mind helped me come back," he added.
Jelonch starts at No. 8 against Uruguay this week in a lineup in which all but three players have been changed from the pulsating opening victory against New Zealand.
He takes over the captaincy from his best friend from high school and the current symbol of French rugby, scrum-half Antoine Dupont.
Fellow squad members No. 8 Gregory Alldritt as well as hooker Pierre Bourgarit also grew up in the Gers.
"I think with time and experience (Jelonch) has learnt to take on the role," Bourgarit said.
"There's no doubt he'll give his maximum tomorrow," he added.
Australian 'hell'
Jelonch made the first of his 25 Test appearances in November 2017 but had to wait three years to claim a place in the squad on a consistent basis.
The following summer, he led Les Bleus for the first time in a three-match tour to Australia in 2021, with strict Covid-19 restrictions still in place.
A third-string France outfit won the second Test, their first win on the road against the Wallabies since 1990, with Jelonch at the forefront.
"It went well even if we didn't win all the matches," Jelonch said.
"We were close in the two other matches, it was tight when we were promised hell.
"It helped me grow as a captain and as a leader," he added.
A French win over the Uruguayans in Lille would be a crucial step towards reaching the knock-out stages and edging towards the goal of lifting the Webb Ellis trophy at the end of October.
"I worked really hard to give myself the chance to be back," Jelonch said.
"To be back for this World Cup as captain is a huge moment of pride for me.
"I will do everything to lead my team-mates to victory."