The question really is : how many rounds has he played in practice recently, has he been doing PT for the back, etc. If he hasn't played a lot of golf, and hasn't been working on the back (that was clearly a problem last season) then he definitely isn't ready to be out there. Why would you even play in a tournament if you weren't 100%
I agree with most of you, he was shooting a horrid round and the back complaint was a convenient excuse. Did it hurt? Very possibly, did it hurt enough to not finish the last four or five holes? Probably not. I mean he did play just OK thurs/fri but shot great Saturday. I'd think coming off the 65 (which showed improvement over the previous days) that he was looking for a strong finish. So yeah, I dont doubt his back hurt. But I also again do think it was a convenient reason to not finish that horrid round.