Based on the diquark-cluster model, the mass spectrum of low-lying S=-1 strange dibaryons is predicted. In this scheme, two ${J}^{P}$${=0}^{\mathrm{\ensuremath{-}}}$ states with I=(1/2 and (3/2 are degenerate at the lowest-energy level, around 2.2 GeV c.m. energy. These states can be assigned to the strange-dibaryon candidate at 2.14 GeV observed by Piekarz in the missing-mass spectrum for the d(${K}^{\mathrm{\ensuremath{-}}}$,${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$)X reactions. A similar experiment using polarized deuterons is proposed for the purpose of testing the validity of this assignment.