Reeeeelax ... Donald Trump's mouthpiece says POTUS was only tweeting "rhetorically" when suggesting he should have left LaVar Ball's son in a Chinese jail.

Yep.

Sarah Huckabee Sanders just addressed the media ... and was asked about Trump's tweets in which he said LaVar was "unaccepting" of what he did for LiAngelo Ball and "I should have left them in jail."