Thing that gets me is that it states he was undergoing treatment for back pain when he aggravated a pre-exisiting injury. I take that to mean the original injury didn't occur on the job. In my 9-5 day job, one of our insurance policies is with Liberty Mutual. I'm not 100% on worker's comp rules (my co-worker handles WC...I handle Auto and Property Damage claims) - but I believe that if you have a pre-existing injury and "aggravate" it while on the job, that may be grounds for a denial from the insurance company, depending on the state laws. I can ask my co-worker when he's in the office.
