It is known that, at energies below the deuteron breakup, nd scattering
in the doublet channel exhibits both a virtual state and a zero in the
amplitude. We construct a halo/cluster EFT that takes both features into
account, and follow the behavior of observables as we decrease the deuteron
binding energy. Reaching the unitary limit, we demonstrate the nature of this
virtual state associated to an excited Efimov state, confirming previous
studies using phenomenological models.