  Available experimental data on the exclusive $pd\to pnp$ reaction at 585 MeV
show a narrow peak in the proton-neutron final-state interaction region. It was
supposed previously, on the basis of a phenomenological analysis of the shape
of this peak, that the final spin-singlet $pn$ state provided about one third
of the observed cross section. By comparing the absolute value of the measured
cross section with that of $pd$ elastic scattering using the F\"aldt-Wilkin
extrapolation theorem, it is shown here that the $pd\to pnp$ data can be
explained mainly by the spin-triplet final state with a singlet admixture of a
few percent. The smallness of the singlet contribution is compatible with
existing $pN\to pN\pi$ data and the one-pion exchange mechanism of the $pd\to
pnp$ reaction.
