"I do not expect Ronaldo to do more or less than he did in the first three games, they were all waiting for Ronaldo and he (Mario) Mandzukic.
"I think tomorrow could be your day."
And Allegri insisted that the five-time winner of the Golden Ball should lift the FIFA world player award for the sixth time after his performance at Real Madrid last season.
Ronaldo has been shortlisted along with Luka Modric, star of the Croatian World Cup, who beat the Portuguese in the UEFA Player of the Year award, and the Egyptian Mohamed Salah.
"No offense to Luka Modric, I would give Ronaldo the Golden Ball for what he did last season, I think he deserves it," said Allegri.
Ronaldo scored 44 goals for Real Madrid last season, including 15 in the Champions League on the way to his third consecutive title.
Meanwhile, Allegri said he would make changes against Sassuolo, second in the league behind Juventus, with a view to next week's trip to the Champions League in Valencia.
"This is where the season starts in earnest."
"Our first goals are to qualify for our Champions League group and lead the way in the league to be able to fight on all fronts since March."
German midfielder Emre Can should have his first start since arriving from Liverpool during the summer, with Miralem Pjanic and Giorgio Chiellini probably resting.
"It should be the first start tomorrow for Emre Can, who came from a different football style and it was natural that he would need a period to adjust, especially after an injury," said Allegri.
The Juventus coach insisted that there was room for Argentine striker Paulo Dybala, the club's top scorer last season, despite the arrival of Ronaldo.
"When you have so much talent in the team, someone has to sit down," he said.
"The quality of Paulo is not in debate, but I have to choose 11 players plus three others to leave the bench.
"Paulo has to show that he deserves his place in the starting lineup.
"I am very happy with the way he left the bench in Parma during the last 15 minutes, since he already had a completely different approach."