So, my question is, does this loosely connected
skull indicate that certain predatory dinosaurs (Bakker, though the term
seems to include tyrannosaurs, and that's strange; F & W title the
section from which the quote was taken Theropods as Living Organisms) were
incapable of using their heads as a main weapon in hunting, at least in
hunting sizable prey?
No it doesn't. I'm sure that most
predatory dinosaurs used their jaws as their main weapon. The skull
bones that needed strength (maxillae, dentaries, etc) were built to handle
stress. Tyrannosaurid tooth marks on bones indicate they could bite
with plenty of force, and although most other large theropods' skulls
weren't built as heavily, I'm sure they were effectively designed for
handling stress as well. As for the smaller theropods with lighter
skulls, they were going after smaller prey. Besides, what else
(excepting killer claws on dromaeosaurs, etc.) could theropods use to
inflict enough damage to kill their prey?