John Cena, Daniel Bryan's soon-to-be real-life brother-in-law and fellow WWE superstar, says Daniel's done "everything possible" to get back in the squared circle ... and John couldn't be happier for him.
"He's gone through every single protocol, 10-fold," Cena told TMZ Sports at Montage in the Beverly Hills. "He's one of the healthiest people in WWE, and it just takes a lot of convincing of other minds that he's that healthy."
Those minds, according to WWE, are a team of "leading neurosurgeons, neurologists and concussion specialists" in their fields ... who've medically cleared Bryan after almost 3 years on the sidelines due to post-concussive symptoms.
John's clearly on board with their diagnosis ... and told us no one deserves a comeback shot more than the former champ behind the "YES!" movement.
"He worked his ass off to make that happen," Cena said. "It is what he was born to do ... he's back where he belongs."