Does this means that it's possible that he's also going to be out of NBA and won't play for the Cavs when the regular season starts if he's not yet okay?
Nah, I don't think he'll give up his NBA career, it's a bit early for the 2019 FIBA MVP to give up this early. I mean that's his bread and butter right there and his passion as well. If he thought skipping the FIBA world cup could bring goodness to his career, pretty much everyone in the same shoe will do the same. It's also good for his mental health that the Spanish team respected his decision.
He should be more ready in the coming season so he won't lose but improve his value, otherwise he's going to disappear unnoticeably like the other role players in the NBA, since he's actually close to it after recovering from an injury he was struggling real hard when he have rejoined his team in the middle of the season.
Ricky Rubio is still young at 32 years old, (although I thought that he is a bit older). It's good that we here sports athletes citing mental health as a issues and it's concerning.
However, I also do agree that he won't simply retire because of that reasons, maybe he just nee to skip the World Cup and the pressures of playing for his country again. And he is coming from injury too and perhaps this contributed to his having a mental breakdown. Nevertheless, if he is still as competitive as he is, then he will continue to play in the NBA.