Football

But, brittle.
Plus, Charles Martin ruined his career with an act that would have been felony assault off the football field.
If he could have stayed healthy, he would at least been in consideration for the HoF.
He was very efficient, could escape pressure, he read defenses better than any Bears QB ever, and his offense loved him.
He had the misfortune of playing at the sane time as Montana, Marino, & Elway. That's an impossibly high standard.