Sarri, 60, was said to have been suffering with flu, but a statement released on the official Juventus website said the Italian had contracted pneumonia:
"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 authorized the club to communicate his state of health."
Aaron Flanagan of the Mirror wrote it was unlikely he'd be at the Juve touchline for their visit to Parma.
The report included quotes from Sarri, who recently said he currently smokes around 60 cigarettes per day: “It’s 60 a day, probably a few too many. I don’t particularly feel the need to smoke during games, but straight afterwards it really is necessary. I had back problems tormenting me for weeks, but I feel much better now.”
Sarri left Chelsea in June after one season at the club, finishing third in the Premier League and leading the Blues to the UEFA Europa League crown.
The former Napoli manager said at his Juventus unveiling that he was ready to prove his ability to sceptics, having failed to crack the Bianconeri's grip on Serie A during his three years at Napoli:
One would assume Sarri's assistant manager, Giovanni Martusciello, would be the man to take over in his stead should he miss any fixtures, though no official decision has been announced.
Following the trip to Parma, Juventus host Napoli in their first home fixture of the season on Saturday, August 31.
Sarri may well relish an early meeting against his old club, though reports of his illness put his involvement in doubt for that and future fixtures.