Dusan Vlahovic ready but Federico Chiesa a doubt as Juventus take on Milan
Vlahovic was unavailable for the Serbia squad during the international break having missed Juve's last two games with a back injury.
"Vlahovic has been working with the team all week and is fine," Allegri told a press conference on Saturday.
"From the start? We'll see, he certainly doesn't have the full 90 minutes in his legs having been out of action."
Chiesa, meanwhile, did join up with the Italy squad even though he missed Juve's 2-0 win over Torino with a muscle injury, but returned to his club before Italy's games with Malta and England.
"Chiesa completed half the training session on Friday, today we will evaluate whether he will be available and whether to call him up or not," said Allegri.
"I hope to have him available, tomorrow (Sunday) will be a game where substitutions can be decisive and therefore the more players we have, the better it will be."
One player who won't be a part of the manager's plans is Nicolo Fagioli, who began a seven-month ban on Thursday for breaching rules on betting on games.
"I spoke with Fagioli, because it was right to do so, given that it won't be an easy period for him," Allegri said.
"He, however, knows very well that everyone, the club, staff and teammates, are waiting for him with open arms. He must be supported and we are there for him."
With both Alex Sandro and Danilo out injured, Adrien Rabiot will start as captain for the first time. The French midfielder has played every minute of Juve's season to date.
Juventus are third in the table, and travel to the San Siro to take on leaders Milan, with four points separating the sides.