Portugal will have to make do without its captain Cristiano Ronaldo in its upcoming World Cup qualifier against Switzerland. The 31-year-old, who was crowned best player in Europe after helping Portugal win its first European championship title this summer, remains sidelined with a knee injury.

“I have been told that Cristiano Ronaldo is clinically unfit,” Portugal Coach Fernando Santos said at a press conference on Friday (via Agence France Presse).

Ronaldo suffered the injury to his left knee in the first half of the Euro 2016 final against France on July 10 when on a challenge from Dimitri Payet, Ronaldo attempted to run the injury off, but he ended up being stretchered off the pitch.

Details of the exact nature of Ronaldo’s injury have remained murky. Spain’s Marca newspaper reported last month that the star has a ligament strain, for which ESPN FC reported he underwent hyperbaric oxygen therapy while on vacation in Ibiza.

Ronaldo re-joined his club Real Madrid on Aug. 10, but has not played in any of the team’s preseason games.

Ronaldo showed up at the Champions League group-found draw on Thursday to collect his trophy after being named UEFA’s best player, but declined to talk about his prognosis or when he might return to play.

Meanwhile, Portugal has set its 24-man squad ahead of the Sept. 6 showdown against Switzerland. Without Ronaldo, Portugal named Rafa Silva (Braga), Bernardo Silva (Monaco), Nani (Valencia), Ricardo Quaresma (Besiktas), Andre Silva (Porto) and Eder (Lille), who scored the winning goal against France in the Euro 2016 final as its strikers.

Midfielders include: William Carvalho (Sporting Lisbon), Danilo (Porto), Joao Moutinho (Monaco), Adrien Silva (Sporting), Andre Gomes (Barcelona), Joao Mario (Sporting Lisbon) and Renato Sanches (Bayern Munich).

The defenders are Joao Cancelo (Valencia), Cedric Soares (Southampton), Pepe (Real Madrid), Bruno Alves (Cagliari), Jose Fonte (Southampton), Luis Neto (Zenit St Petersburg), Raphael Guerreiro (Borussia Dortmund) and Eliseu (Benfica).

And the goalkeepers: Rui Patricio (Sporting Lisbon), Anthony Lopes (Lyon) and Eduardo (Dinamo Zagreb).