Considering the interest in the understanding of the properties of phosphorene-based materials, this work is aimed to clarify the origin of the quantitative and relative stability of TM dopants on phosphorene by density functional theory. We focus the attention on the physical/chemical phenomena dominating the doping stability in adatom and substitutional schemes. From the physical point of view, energy decomposition analysis based on absolutely localized molecular orbitals (ALMO-EDA) will allow us to characterize the binding strength in terms of physical terms easy to interpret (electrostatic, polarization, dispersion, charge transfer, and Pauli repulsion). From the chemical point of view, the atoms-in-molecules (AIM) and natural bond orbital (NBO) analyses will be used to obtain the chemical fingerprint of the bonding (electron density at the bond critical points and strength of donor-acceptor orbital interactions).