The record that Ronaldo got did not want to be replaced by Messi because the goal difference between the two was quite thin, and that became one of the ambitions why Ronaldo was so adamant about leaving and moving clubs. As you said, I'm referring more to Sporting which will be the place back where he started his career.
We know that Sporting is a club that can still be said to be good but the Primeira Liga will not be enough to accommodate Ronaldo now because indeed I don't even here see a thread about this league based in Portugal.
He could go there but I think with the ambition he has now, it's not the right time for him to go back there.