Juventus defender Lucio is likely to face a long spell on the sidelines after damaging ankle ligaments in training.
Lucio only joined Juve last month after his contract with Inter Milan was cancelled and was preparing to make his Serie A debut for the champions against Parma on Saturday.
However, he suffered the injury during the final practice session ahead of the game and tests have confirmed the extent of the damage.
"Lucio has undergone medical tests after twisting his right ankle in training on Friday," read a medical update on the club's official website.
"The X-ray and MRI scans, which were conducted on Saturday morning, have revealed a complete tear of the defender's anterior talofibular ligament."
Juve, who started the defence of their title with a 2-0 win over Parma, must now decide whether to sign a replacement before Friday's transfer deadline.