The 37-year-old previously expressed a desire to leave Old Trafford before missing the pre-season tour to Thailand and Australia due to family reasons.
Ronaldo returned to training last week and featured in the first half of United's 1-1 draw against Rayo Vallecano on Sunday.
Despite featuring in the friendly meeting, the Manchester Evening News are reporting that the Portuguese International still wants to leave this summer.
The player's agent Jorge Mendes is reportedly doing 'everything he can' to find his client a new club in the current transfer window.
Chelsea, Bayern Munich and Atletico Madrid have ruled themselves out of the race to sign Ronaldo, while there have been reports linking Napoli and Sporting Lisbon with a move.
With no transfer appearing to be imminent, Ronaldo could be included in the squad for United's Premier League opener against Brighton & Hove Albion on Sunday.