The midfielder did not feature in Juventus' final fixture in their pre-season tour of Asia but the Bianconeri coach insisted he was merely protecting the player's fitness
Goal understands that the Chile international's representatives have already met with United officials this summer, although Juventus have maintained throughout the window that they have no plans to sell the midfielder.
After returning to training with his Juventus team-mates this week following an extended break after the World Cup, Vidal had been expected to play some part in Saturday's pre-season clash in Singapore - but the 27-year-old did not feature at all.
However, Allegri insisted that he was simply unwilling to take any chances with the fitness of either Vidal or Carlos Tevez, who did not see any game time either.
"It was a precautionary measure taken in order to avoid any pointless risks given the state of the field of play was not good," the Bianconeri boss told reporters after his side's 5-0 win.
"Next week [Vidal] will be with the team."
Allegri, of course, only assumed control of Juventus this summer, after the surprise resignation of Antonio Conte.
Given his predecessor had led the club to three successive Serie A titles, Allegri says his primary focus is on cracking Europe.
"My first goal for the season will be to get through the group stage of the Champions League," the ex-AC Milan boss said.
"It's a very difficult competition, so we need to be ready to get to our maximum level and go as far as possible."