Jay Glazer -- Chris Johnson Injury Is Nothing ... Compared to Gunshot!!!

If you can come back from a BULLET WOUND you can come back from a cracked tibia ... so says Jay Glazer who tells TMZ Sports Chris Johnson WILL return to the NFL this season.

The AZ Cardinals RB suffered a broken tibia against the SF 49ers this weekend ... and some feared he could be done for the year -- which sucks considering he's been playing out of his mind.

But Glazer says Johnson's not your average guy when it comes to bouncing back -- and the proof is how quickly he was able to recover from the gunshot wound suffered in a drive-by earlier this year.

"Guy got shot in the shoulder. If you can come back from that, it'll be alright with the tibia."

Glazer has personal stake in the matter -- he's not only good friends with Johnson but trains him at his famous Unbreakable training center in L.A.