  A QCD formula for the polarization in the large-p_T \Lambda hyperon
production in the unpolarized nucleon-nucleon collision at large x_F is
derived. We focus on the mechanism in which the chiral-odd spin-independent
twist-3 quark distribution E_F(x,x) becomes the source of the transversely
polarized quarks fragmenting into the polarized \Lambda. A simple model
estimate for that contribution shows the possibility that it gives rise to a
sizable \Lambda polarization.
