Juventus are likely to be without defender Martin Caceres for the rest of the season after he fractured an ankle in training on Sunday.
The Uruguayan, who had regained a regular starting place after missing much of the first half of the season with a thigh injury, will have surgery on Monday.
"Martin Caceres is to undergo surgery after fracturing the malleolus bone in his left ankle during this afternoon's training session," a statement on the Turin club's website said.
"The defender will be operated on tomorrow, with a prognosis on his recovery time to be established afterwards."
Meanwhile, coach Massimiliano Allegri called for perspective after the 2-1 defeat at home to Fiorentina in the Coppa Italia -- the first loss at the Juventus Stadium in almost two years.
"This team has won three scudettos in a row, and it seems to be taken for granted that they've got to do the same again this season," he told a news conference.
"I think that a bit of enthusiasm has fallen by the wayside and that winning four titles in a row is not easy -- very few clubs have succeeded in the past.
"We should instead all be proud of what these lads are doing. The league's not won yet, and it's unimaginable to think it might have been over already in February.
"We need a bit of perspective, and we need to carry on working hard and looking at the positives, trying to limit the negatives."
Juve can open up an 11-point gap at the top of Serie A if they beat Sassuolo on Monday.