The smart thing to do is to report it to the workers comp carrier and let them decide if it's covered.
This is a win-win situation for the employer. If it is workers comp, you're covered because it's in process. If it's not, then you are not the evil employer who refused to submit the claim, but the helpful employer who is only reporting what the evil workers comp carrier decided. You can then help the employee report the incident to her standard health insurance carrier. They won't pay lost wages (if she loses enough time AND you have a short term disability carrier they might) but they'll pay the medical bills as long as she has a denial letter from the workers comp carrier.

