Canadian midfielder Marcelo Flores will miss the World Cup after suffering a torn anterior cruciate ligament while playing for Tigres UANL.
The 22-year-old was injured in Saturday's Concacaf Champions Cup final, going down without contact in the 77th minute and clutching his right leg before leaving the pitch in tears.
Flores confirmed the injury on social media.
"My ACL is gone," he wrote on Sunday. "I wanted to say thank you to everyone and all the messages. I haven't been on my phone or checked messages, but I promise to get around to everyone and I really appreciate the concerns. I'll be back stronger."
Canadian coach Jesse Marsch told reporters on Sunday that he and the team were "devastated" by the news.
Marsch had named Flores in his 26-man World Cup squad on Friday, with other key players including Bayern Munich's Alphonso Davies still working back to full fitness.
Flores was born in Canada to a Mexican father, making him eligible to play for either country. He switched allegiance from Mexico to Canada earlier this year, and featured for Canada in games against Iceland and Tunisia.
Canada face Uzbekistan in a friendly in Edmonton on Monday. They open their World Cup campaign against Bosnia and Herzegovina on June 12 in Toronto.

England dismiss Pakistan for 110 to seize control of Lord's test
Raphinha, Fermin score as Barcelona beat Athletic in home opener
Celtic and Rangers to play cup match behind closed doors after pitch invasion
Chelsea and Fulham reach League Cup third round as Welbeck scores on debut
PSG to meet Barca, Man City as Champions League draw throws up marquee ties