The suitability of the Eddington approximation as a theoretical framework for the study of the possibility of a k-like overstability mechanism as the driving force of solar modes of oscillation is assessed. A theoretical description of the interaction between the hydrodynamics of the motion and the radiative energy transport is needed. It is found that the multidimensional Eddington approximation is generally adequate for giving account of the radiative damping effects of Planck function fluctuations, while it is in gross disagreement with the exact results with respect to the radiative transfer effects of opacity fluctuations. Therefore, it is concluded that its use should be avoided when investigating k-like excitation mechanisms for nonradial stellar modes of oscillation.