Dufner couldn't shoot a 63 either, until he shot one.
Putting is like three-point shooting. You can go through slumps, and even the best ones have their dry spells. Doesn't mean you no longer have the skill when you struggle. Not like what you go through when you lose your swing and can't get greens in regulation. Then you're screwed.
Tiger wasted his A game last weekend. Happens. He went three years between his first Masters and Major #2, so he's been here before. Just remains to be seen if he pulls it together in a couple majors before his window closes.