Focus immediately turned to the Italian side’s clash with Ajax in 11 days time.
The Portuguese star is due to have a scan on Monday and Allegri admitted he would rather wait until Ronaldo is fully fit before unleashing him again.
“Prudence is always useful, it is better to skip a game than two months,” said the Juventus manager.
“We are in a delicate phase, we have 10 games in the league and, for now, two in the Champions League.
“He will be back when there is no danger of a relapse.
“On Monday he will have a scan, from then we will evaluate. There are so many risks for the away game with Ajax. He also knows that if he is not well then he will not play.”
Ronaldo has also made the headlines for other reasons:
Ronaldo’s hat-trick turned their last-16 tie with Atletico Madrid on its head.
The Serie A champions had lost the first leg 2-0 in Madrid, but Ronaldo’s efforts went someway to justifying his huge transfer fee.
Ajax stunned Ronaldo’s former side Real Madrid in the last round, but are still seen as a favourable draw at this stage of the competition.
The first leg will take place in Amsterdam before the sides return to the Allianz Stadium six days later.
Ronaldo will invariably sit out his team’s clash with Empoli this weekend.
The Bianconeri are 15 points clear in Serie A and have placed huge emphasis on finally ending their wait for a European triumph.
Allegri was, on Friday, dealt further bad news with reports emerging that major summer target James Rodriguez is set to sign for Bayern Munich.
The Colombian’s two-year loan deal with the Bundesliga side expires this summer and Juventus had hoped to pounce, but the Germans hold the upper hand.
