I did a little googling and it looks like these things are galls caused by wasps and that we don't necessarily have to worry. I'm still concerned about the leaf discoloration though -- any thoughts?

Oaks are prone to more types of galls than just about any other tree species. And for the most part, they are harmless if not particularly attractive. Your photo is not clear or detailed enough to make any sort of assessment on leaf color. Maybe a shot of the whole tree or a larger view and close ups of the leaves in question? Anything different going on this season compared to previous ones? Is the tree in the lawn? Do you fertilize or other lawn treatments?

Twig and stem galls are about the only types that would worry me, if the infestation is severe. A few wouldn't bother me and shouldn't you, either.

Agree with gardengal that more information and images are needed regarding your tree.

How large is the tree? How long has it been in its present location?