However, he appeared to be content as he uploaded an envious selfie of himself in a pool to Instagram. He just wrote'relaxing' and gave it a thumbs up while wearing his own branded shorts, which may have been boxers.
He left training early due to a new injury, which caused him to miss the trip to Villa Park, according to SunSport exclusively.
"With Ronaldo, it's unfortunate, it's still the same situation," interim chief Ralf Rangnick remarked.
"I talked to him before and after training yesterday, and he decided he wasn't entirely fit, but maybe he'll be available on Wednesday."
Ronaldo was examined by United's medical staff before being driven home, where he would utilize his own private oxygen chamber that he had installed in his home.
It helps with injury recovery by inhaling pure air directly into blood plasma, which helps to restore any damaged tissue.
Since his return to Manchester in the summer, the 36-year-old Portuguese international has made 26 appearances for club and country.
Last week, SunSport reported that Ronaldo is dissatisfied with interim manager Rangnick's approach.
"Cristiano is genuinely concerned about what is happening at United," a source close to Ronaldo claimed.
"The squad is getting a lot of flak, and he's well aware that he's one of the leaders."
"There are a lot of issues, and Cristiano is under a lot of stress as a result of the situation."
"He is keen for his United move to be a success, but he is beginning to see how difficult it will be to win titles with the current squad."
"Jorge came to meet him, and they spent some time talking about how things are going, what the difficulties are, how they may be fixed, and what the answers might be."
"Nothing is off the table."
-7msport.