The ejected-electron excitation functions of the J = 3/2, 1/2 components of the (2p(5)3s(2))P-2 leading autoionizing doublet in sodium atoms were measured at an incident electron energy resolution of 0.25 eV over the incident electron energy range from the lowest excitation threshold up to 36 eV. On the basis of 56-state R-matrix (close-coupling) calculations, the observed strong near-threshold structures were classified as negative-ion resonances with likely configurations 2p(5)3s(2)3p and 2p(5)3s3p(2).