In most cases, yes. Employees who are hurt at work--even if the actions were not part of their job--may still recover workers' compensation benefits. The North Carolina Industrial Commission has taken the position that injuries that result from the gathering of workers stem from the business. This is typically interpreted as meaning the worker would not normally come into such close contact with other workers and is only exposed to them as part of their job.
The term 'horseplay' may encompass joking, goofing around, roughhousing, and more. Every case is unique, and the cirumstances of events should be reviewed with a workers' comp attorney. If the injured worker was the individual instigating the horseplay, and then was subsequently injured, they may still be eligible for workers' comp benefits. Learn more about workers' comp claims when the on-the-job injury was your fault.