The 33-year-old left the pitch in tears, while Juventus manager Massimiliano Allegri said the forward would have avoided a red card if VAR was in use in the Champions League.
The UEFA Control, Ethics and Disciplinary Body may extend the mandatory one-match ban.
The encounter will see Ronaldo make an emotional return to Old Trafford, before facing United again, in Turin on November 7.
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"It was a soft sending-off for Ronaldo, but the letter of the law says you probably can not do that, so I think the one-match ban will probably stick".
"If I had been officiating this game, I would have given Valencia a free-kick and shown a yellow card to each player".
"He will feel like he was letting his team-mates down in that moment, but I expect him to play in both games against Manchester United", he submitted.
The reported punishment means Ronaldo will miss Juventus' home game against Young Boys on October 2 but will be available to face former club Manchester United on October 23 at Old Trafford.
UEFA has confirmed disciplinary proceedings have been opened against Cristiano Ronaldo following his red card in Juventus' Champions League victory in Valencia on Wednesday.
"Going down to 10 men in the Champions League for an incident like that is disappointing".