  A common approach to the quantization of integrable models starts with the
formal substitution of the Yang-Baxter Poisson algebra with its quantum
version. However it is difficult to discern the presence of such an algebra for
the so-called non-ultralocal models. The latter includes the class of
non-linear sigma models which are most interesting from the point of view of
applications. In this work, we investigate the emergence of the Yang-Baxter
Poisson algebra in a non-ultralocal system which is related to integrable
deformations of the Principal Chiral Field.
