  Recently, the GWU lattice group has evaluated high-precision phase-shift data
for $\pi\pi$ scattering in the $I = 1$, $J = 1$ channel. Unitary Chiral
Perturbation Theory describes these data well around the resonance region and
for different pion masses. Moreover, it allows to extrapolate to the physical
point and estimate the effect of the missing $K\bar{K}$ channel in the
two-flavor lattice calculation. The absence of the strange quark in the lattice
data leads to a lower $\rho$ mass, and the analysis with U$\chi$PT shows that
the $K \bar{K}$ channel indeed pushes the $\pi\pi$-scattering phase shift
upward, having a surprisingly large effect on the $\rho$-mass. The inelasticity
is shown to be compatible with the experimental data. The analysis is then
extended to all available two-flavor lattice simulations and similar mass
shifts are observed. Chiral extrapolations of $N_f = 2 + 1$ lattice simulations
for the $\rho(770)$ are also reported.
