If the statements are arguably defamatory, the employee may have a personal injury claim against you. Below is a discussion of each element as it may pertain to you in that situation. But it must be false.
Truth is an absolute defense to a defamation claim.
In some instances, statements such as those about an employee's competence, may be deemed to be pure opinion and therefore not defamatory. The publication of a defamatory statement means communicating it to someone other than the defamed person, whether intentionally or negligently. Delaware courts have consistently held that when persons acting within the scope of their employment and on the employer's behalf make a defamatory statement, they have a conditional privilege and thus are generally protected from a defamation claim. In short, employers will have extra protection from defamation claims in most contexts. The manager may have been negligent in putting the false statement in the file by taking someone else's word about the statement without doing thorough research to confirm its truth.