  We analyze the expectation value of the Polyakov loop in the fundamental and
higher representations in the confined phase of QCD. We discuss a hadronic like
representation, and find that the Polyakov loop corresponds to a partition
function in the presence of a colored source, explaining its real and positive
character. Saturating the sum rules to intermediate temperatures requires a
large number of multipartonic excited states. By using constituent or bag
models, we find detailed low temperature scaling rules which depart from the
Casimir scaling and could be tested by lattice calculations.
