Regis Harrington pulled the jump Wednesday while shooting a scene in Atlanta ... but a source on set tells us he lost control upon landing. We're told he was immediately rushed to Atlanta Medical Center, where he was under observation in the ICU for a back injury.

The good news is, Regis -- a seasoned vet who's performed stunts for movies like "Logan," "Jurassic World," and "Captain America: Civil War" -- tells us he's gonna be okay.

We got ahold of him on Thursday and there was no bitterness over the stunt gone wrong.

In fact, Regis says he made a mistake while riding ... and he gave the "MacGyver" crew full props for handling the accident with care and professionalism.

CBS confirmed a stunt performer felt pain in his back after a motorcycle stunt and was "transported to a hospital for diagnostic testing."

Regis told us he'd already been released.