Hugo Lloris is set to be out of action until next year after further tests on a dislocated elbow revealed ligament damage, Tottenham announced on Monday.
The World Cup-winning goalkeeper fell awkwardly after failing to collect a cross as Spurs were beaten 3-0 at Brighton on Saturday.
The Premier League club confirmed the injury later that evening but had not put a timescale on a possible return.
However, following more tests, it was confirmed the 32-year-old is expected to miss the remainder of 2019.
"Hugo Lloris has undergone further assessment this morning after sustaining a dislocated elbow in our match against Brighton on Saturday," Tottenham said in a statement.
"The findings have shown that although surgery will not be required, our club captain has suffered ligament damage and is not expected to return to training before the end of 2019.
"Hugo is currently in a brace and will now undergo a period of rest and rehabilitation under the supervision of our medical staff at Hotspur Way."
Speaking shortly before Tottenham's announcement, France boss Didier Deschamps issued a similar prognosis.
Lloris, captain of both Spurs and France, would have joined up with Les Bleus for the upcoming Euro 2020 qualifiers against Iceland and Turkey but now misses out.
"He has had tests. It is difficult to say how long he will be out, I am not a medical specialist," Deschamps told a press conference.
"As far as we (France) are concerned, he obviously will not be with us for this camp, nor the next one.
"Processes will be put in place for his rehabilitation. We are talking several weeks, indeed several months.
"He will not return to the pitch in 2019, that's almost certain."
Deschamps admits France will be missing a "very important" player but has backed the likes of Alphonse Areola, Steve Mandanda and Mike Maignan to shine in Lloris' absence.
"It's hard to quantify but he is a very important player – it's a loss for us," he added.
"But we have played without him before, even if he has not had a long-term injury like this before in his career.
"Other players will take over to allow the team to continue to perform."
