Juventus manager Maurizio Sarri has said Cristiano Ronaldo is doubtful for Wednesday's Coppa Italia semifinal return leg against AC Milan as he deals with a "personal problem."

The Portugal captain travelled to Madeira to visit his mother, Dolores Aveiro, on Tuesday, who is reportedly recovering in a hospital in Funchal after suffering a stroke.

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Ronaldo's former club, Sporting Lisbon, tweeted their support on Tuesday: "Sporting Club Portugal wishes Dolores Aveiro, ambassador of the Club's Foundation and an unmistakable reference for all our members, a speedy recovery."

Asked about Ronaldo's availability for Wednesday's game in Turin, Sarri said in a news conference: "Cristiano is going through a strictly personal problem and his availability tomorrow will depend on how that problem goes, once he returns, if he wants, he will talk about it."

Ronaldo has scored 25 goals in 31 appearances in all competitions for Juventus this season and his absence will be a big setback Sarri said.

"It is clear that the possible absence of Cristiano could cause us to change things tactically," he added. "There are no substitutes for him in the world."

Juventus drew the opening leg 1-1, and the return will see no supporters from the Milan region allowed in the stadium due to the coronavirus outbreak in Lombardy.