  We analyze meson-baryon scattering lengths in the framework of covariant
baryon chiral perturbation theory at leading one-loop order. We compute the
complete set of matching relations between the dimension-two low-energy
constants in the two- and three-flavor formulations of the theory. We derive
new two-flavor low-energy theorems for pion-hyperon and pion-cascade scattering
that can be tested in lattice simulations.
