- Don't have ESPN? Get instant access
"Yesterday, Cristiano Ronaldo communicated to me that he has no intention of remaining at Juventus," Allegri told a news conference ahead of Saturday's Serie A clash with Empoli. "For this reason, he has not been selected."
Asked if he was disappointed in Ronaldo's decision to leave, Allegri said: "No. He made a choice. [Omar] Sivori, [Alessandro] Del Piero, [Zinedine] Zidane have come and gone. Juve remains and that's the most important thing."
In Italy, he won back-to-back Serie A titles in his first two seasons.
Former teammate Wayne Rooney has questioned the proposed move.
"I don't know what to make of it, to be honest," the Derby County manager told a news conference. "If you're asking me if I think it's possible then I have major doubts that it is a possibility.
"Cristiano has got a great legacy at United. I don't think he's going to move somewhere for financial reasons."
Obstacles would still have to be overcome before the transfer is done -- particularly Juventus' demand for a fee -- but there is cautious optimism a deal can be reached, sources said.
Juve would want around €28 million before allowing Ronaldo to leave but there is a keenness to get the 36-year-old off the wage bill.