The Portuguese defender is not fully match fit and could be forced to sit out this weekend's match due to a head injury
The former Portugal international sustained the knock in the closing stages of his side's scoreless draw against Racing Santander on Wednesday.
Carvalho was unable to take part in Thursday's regular training session due to he head injury, instead visiting a hospital for further examination.
The 33-year-old was allowed to return home immediately after undergoing a number of tests, but it is unlikely that he will feature in Saturday's home game against newly promoted Rayo.
Carvalho's injury is yet another blow for Mourinho, who is already without the likes of Pepe, Fabio Coentrao and Nuri Sahin due to various health problems.