Absolutely a shell.
The question now isn't will he beat Jack. The odds of that are extremely low. The question is, will he win even one more Major.
I lean to this point of view... but Couples and Watson have shown guys older than him can hang around Majors. If Tiger can really recover physically, he should have more opportunities to win 1 or 2 more Majors. After all, he was good last year (not his former self) but winning tournaments, and ranked #1.
Where I really agree with you though, is that I think the chase of Jack is over. I could see him putting things together once or twice... matching Jack? I don't see it.
This latest set-back comes just weeks after Tiger said he felt his best in years. The back could flare at any time.
I think Tiger is going to have to show he can play through 4 rounds, in week-after-week before you really can have confidence of him putting together any type of a run.
If you are a Tiger fan, I think what should be concerning is that for the past couple of years he keeps telling you that physically, and mentally he is close... and then the results show otherwise.