  We obtain the internal degrees of freedom of the skyrmion (spin and isospin)
within a manifestly Lorentz covariant quantization framework based on defining
Green functions for skyrmions and then, the S-matrix via LSZ reduction. Our
method follows Frohlich and Marchetti's definition of Euclidean soliton Green
functions, supplemented with a careful treatment of the boundary conditions
around the singularities. The covariant two-point function obtained propagates
a tower of spin equal to isospin particles. Our treatment contains the usual
method of collective coordinates, as a non-relativistic limit and, because of
the new topology introduced, it leads, in a natural way, to the inequivalent
(boson/fermion) quantizations of the SU(2) skyrmion.
