The Chile international midfielder has been linked with Old Trafford, with new boss Louis van Gaal himself admitting to being a fan of the 27-year-old.
"He's a fundamental player for Juve and he will stay with us," Allegri said in a press conference.
"He feels good and is training.
"His knee must be managed and he will start as a regular."
On the eve of the opening round of Serie A fixtures, Vidal has tweeted a message to his fans, and seems focused on helping Juve retain the Scudetto.
"Ready to start the Championship!" Vidal said.
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