  We review the status of the $S_{11}$ N$^*$ resonances in light of some recent
theoretical and phenomenological results. Whereas the quark model predicts two
such resonances around 1.6 GeV, there is considerable evidence for a third
$S_{11}$ resonance in this energy range. This suggests that a $K\Sigma$ or
$K\Lambda$ quasi-bound state may indeed exist below the kaon production
threshold. We show that kaon production experiments, in particular $K^0$
photoproduction off nucleons, would be very sensitive to the existence of the
third $S_{11}$ resonance.
