Juventus have confirmed manager Maurizio Sarri missed training on Monday, with the club stating he has been diagnosed with pneumonia.
Sarri was struggling with the flu last week but now Juve have confirmed the former Chelsea and Napoli boss has been given specific treatment for pneumonia.
The 60-year-old was at the club's training ground but did not partake in any sessions, instead giving instructions to the rest of his coaching team.
The club revealed in a statement: "Maurizio Sarri, after having observed rest over the weekend, was at the JTC Continassa today where he coordinated the work of his staff.
"Unfortunately, he could not conduct the training on the field due to the persistence of his flu, which struck him over the course of last week. In the late afternoon, he underwent further tests that confirmed he has pneumonia, for which specific therapy has been prescribed.
"The coach has authorised the club to communicate his state of health."
Sarri is about to embark on his first season back in Italian football since leaving Napoli for Chelsea, with Juve expected to face tough challenges from both his former club and Antonio Conte's Inter for the Serie A title.
Sarri is now a doubt for Juve's first league game of the season, which sees La Vecchia Signora face Parma in the Serie A season's opener.