In this work we propose a new perspective in order to unveil the mechanism leading to the spin-orbit de/coupling of light at the nanoscale. Taking into account the factorizability condition of the electromagnetic fields we show, by using the spherical vector wave formalism, that this condition is fulfilled only in the far-field region. On the other side, in the near-field region, amplitude (spin) and phase (orbit) manifest a complex behavior itself, namely, they appear to be coupled with each other according to the spin-orbit coupling regime.