The Portugal centre-back missed out on Monday's training due to a thigh muscle problem and remains a doubt for Wednesday's UEFA Euro 2016 semi-final at Parc Olympique Lyonnais.
In a general press conference, Portugal press officer Onofre Costa revealed the influential defender is suffering from a thigh injury.
"Pepe has a muscle pain in his thigh and is not going to train today as a precaution."
The Real Madrid full-back is considered one of the most important players for A Seleção and has been one of the stand-out performers for Portugal thus far at Euro 2016.
Pepe has started in all of his side's five matches in France.