Paulo Dybala is due to undergo further tests on a thigh injury he picked up at the weekend, with an initial MRI scan suggesting a lay-off which could be up to six weeks.
Dybala was substituted during Juve's 1-0 win at Cagliari on Saturday and was diagnosed on Sunday with a mild to medium strain to his right thigh flexor.
However, more precise tests will be performed on Wednesday, once the muscular swelling has subdued, to discover the full extent of the damage, with doubts being raised as to whether he will be fit to face Tottenham Hotspur in the Champions League round of 16 first leg on Feb. 13.
"He will immediately start rehabilitation with the prognosis for return better evaluated in the coming days," read a statement on the Serie A club's website.
Dybala tweeted that he will "be back soon," but even if the injury is confirmed as just a mild to medium sprain, he will be a doubt for the Bianconeri's next Serie A fixtures against Genoa and Chievo.
The Juve squad has been given nine days off following Saturday's victory, with Serie A resuming after its winter break on Jan. 20, although Juve are not in action again until Monday, Jan. 22.
They will return to training on Jan. 16.
🇮🇹Vittoria importante!Grazie a tutti per i messaggi di affetto,torneró presto!
— Paulo Dybala (@PauDybala_JR) January 6, 2018
🇦🇷Un triunfo importante.Gracias a todos por los mensajes de apoyo, volveré pronto y más fuerte!
🇺🇸A very important win tonight!Thank you all for your support and your messages, I'll be back soon! pic.twitter.com/3swgBg758U
Allegri added that he was relieved to enter the break with a 1-0 victory that keeps them a single point back of Serie A leaders Napoli.
"We didn't react as well as we should've done, the second half was very physical," Allegri said. "It was very important that we bring home the result, so I compliment the lads, as we are still in Napoli's slipstream and have broken away from Inter and Roma...
"Juventus have done our duty very well so far this season, as we are second in Serie A, through to the Champions League round of 16 and the Coppa Italia semifinals."
Federico Bernardeschi tapped in to put Juve ahead in the 74th minute, and though moments later he appeared to use his arm to bring down a cross, no penalty was given.
The hosts were also upset that the goal was given while Leonardo Pavoletti was down injured following a clash with Medhi Benatia, and Allegri sugggested Cagliari had a right to be aggrieved, saying: "I will say that Cagliari did not deserve to lose today.
"VAR is an instrument that was meant to reduce controversy, but instead it has increased it because people don't accept the referee's decision."