We revisit the treatment of radiative decay processes of light-quark qqbar mesons to a pion in the covariant oscillator quark model. Since the pion has an exceptionally light mass compared with other ground-state hadrons, we have difficulty in dealing with pions within the constituent quark model, including the covariant oscillator quark model. The pion is a pseudo-Nambu-Goldstone boson associated with the spontaneous breaking of chiral symmetry in QCD. The NG boson nature of the pion is not incorporated into the covariant oscillator quark model. In the case of the radiative decay processes this difficulty appears as the anomalous behaviors of decay form factors, which come from overlaps between initial- and final (pion)-state wave functions, due to too small mass of the pion. In actual applications so far there has been “physical vs. symmetric” ambiguity on the treatment of mass of the pion. In this talk we present a possible approach to solution of the difficulty with pions in the covariant oscillator quark model.