In any civil cause of action alleging wrongful discharge in violation of Tennessee public policy, including, but not limited to a discharge in retaliation for the exercise of rights under the Tennessee workers' compensation law, the plaintiff shall have the burden of establishing a prima facie case of retaliatory discharge. If the plaintiff satisfies this burden, the burden shall then be on the defendant to produce evidence that one (1) or more legitimate, nondiscriminatory reasons existed for the plaintiff's discharge. The burden on the defendant is one of production and not persuasion. If the defendant produces such evidence, the presumption of discrimination raised by the plaintiff's prima facie case is rebutted, and the burden shifts to the plaintiff to demonstrate that the reason given by the defendant was not the true reason for the plaintiff's discharge and that the stated reason was a pretext for unlawful retaliation. The foregoing allocations of burdens of proof shall apply at all stages of the proceedings, including motions for summary judgment. The plaintiff at all times retains the burden of persuading the trier of fact that the plaintiff has been the victim of unlawful retaliation or wrongful discharge.