Affirmative defense of injury by fellow servant?

The affirmative defense of injury by a fellow servant is a legal doctrine that can be invoked by employers in personal injury lawsuits, particularly in the context of workplace accidents. It asserts that an employee's injury was caused by the negligence of a co-worker rather than the employer's own negligence. If successfully argued, this defense can absolve the employer of liability, as it places the responsibility for the injury on the actions of the fellow employee. This doctrine is rooted in the common law principle that employers are not liable for injuries caused by one employee to another during the course of employment.