Camavinga picked up an ankle injury while representing France on Tuesday evening, and the 21-year-old's fitness will now need to be assessed ahead of Real Madrid's clash this weekend.
The issue is believed to be less serious than initially feared, but according to Mundo Deportivo, he was unable to train alongside his teammates on Thursday, instead working inside the gym.
Bellingham and Valverde are also said to have been absent from the sessions overseen by head coach Carlo Ancelotti, although it is unclear whether either player is a doubt for the game with Athletic.
Bellingham played twice for England over the international break and scored their equaliser in the final stages of Tuesday's friendly with Belgium at Wembley.
Valverde, meanwhile, captained Uruguay in their 2-1 loss to Ivory Coast on Tuesday, with the midfielder playing the full 90 minutes of the contest.
The 25-year-old has been a vital player for Los Blancos this season, scoring once and providing eight assists in 41 appearances in all competitions.
Bellingham, meanwhile, has had an extraordinary first campaign at Bernabeu, managing 20 goals and nine assists in 31 appearances for Ancelotti's side.
Real Madrid will train again on Friday, and it remains to be seen whether either Valverde or Bellingham are able to take part in the main session, while Camavinga's fitness will also be carefully monitored, with no risks being taken at a vital stage of the campaign.
Bellingham has only actually played in one of Real Madrid's last five league games, missing the
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