Courtois ruptured the anterior cruciate ligament in his left knee back in August, and following surgery it was revealed the Belgian goalkeeper would miss all of the 2023-24 season.
Real Madrid moved quickly to sign Kepa Arrizabalaga on loan from Chelsea, and the former Athletic Bilbao keeper has shared deputising duty with Andriy Lunin this season.
As Courtois will not play a single competitive fixture over the course of the season, even if he was to recover before mid-June, when the tournament commences, the keeper has admitted he would not be up to the level required to play in such a prestigious competition.
Courtois told Belgian outlet Sporza: "Due to the injury there will be no European Champions for me. If I'm lucky, I can play another match in May. But then you can never be 100 per cent ready for a big tournament"
The Real Madrid keeper also spoke about the recent public falling out between himself and Belgium manager Domenico Tedesco.
The new Red Devils boss publicly accused Courtois of leaving the camp early after being overlooked for the captaincy in Kevin De Bruyne's absence back in June.
Along with Romelu Lukaku, Courtois is a vice-captain of the Belgian side, but on his 100th cap against Austria, Tedesco decided to hand the striker the armband instead.
In response, Courtois released a strongly-worded statement to refute the manager's comments.
In the statement, Courtois wrote: "This afternoon I was surprised to hear the coach's press conference in which he gave a partial and subjective account of a private conversation we had after the match against Austria.
"I want to make it clear that it is not the first time or the last time that I talk to a coach about issues related to a locker room, but it is the first time that someone decides to tell it publicly. I am deeply disappointed with this, but I want to make it clear that the coach's assessments do not fit with reality.'
In the interview with Sporza, Courtois appeared to cast doubt over whether or not he would be willing to make up with the manager after the incident.
"For me, it's no problem to sort things out like two adults. But where is the middle ground after a breach of trust like this?" Courtois said.
The 31-year-old missed the subsequent game against Estonia three days later in June, with Strasbourg's Matz Sels filling in in Courtois's absence.
Koen Casteels appears to be number one choice to replace Courtois at the finals, but Sels deputised again when the Wolfsburg keeper missed the October international break with injury.