George Foreman is changing course on Colin Kaepernick -- saying there's NOTHING wrong with his decision to protest and even hailing him as a "great football player" who belongs in the NFL. 

Foreman appeared on "TMZ Live" on Thursday and addressed previous comments in which he seemed to question Kaep's patriotism and suggested his protest was misguided. 

"There's nothing wrong with a guy voicing his opinion," Foreman told TMZ Live ... "When you're young you gotta have an opinion. What's the use of being young if you can’t protest?"

Foreman then went to bat for Colin ... "This guy’s a great football player. I can’t see why he doesn’t have a job. He’s that good."

"Any team is gonna be better if they put him on their team. Kaepernick is a great quarterback. He should have a job."