Merih Demiral is expected to miss the rest of Juventus' season and is a major doubt for Euro 2020 after suffering an ACL injury that will require surgery.
The Juve defender had recently displaced Matthijs de Ligt in the starting line-up and scored a third-minute opener during the 2-1 away win over Roma on Sunday.
But Demiral suffered the injury in an awkward landing shortly afterwards and was replaced by De Ligt 19 minutes into the contest.
The Turkey international, 21, joined the Italian champions from Sassuolo in an €18 million (A$29m) move in July and looks unlikely to play again until next season after Juve provided an update on his condition.
"During the game last night [Sunday], Merih Demiral sustained a sprain to his left knee," a Juve statement read on Monday.
"The diagnostic tests carried out at J Medical this morning revealed injury to the anterior cruciate ligament along with associated injury to the meniscus.
"Surgical intervention will be required in the coming days."
Juve are two points clear of Inter Milan at the top of Serie A after 19 matches this season.