  We investigate the inflationary predictions of a simple Horndeski theory
where the inflaton scalar field has a non-minimal derivative coupling (NMDC) to
the Einstein tensor. The NMDC is very motivated for the construction of
successful models for inflation, nevertheless its inflationary predictions are
not observationally distinct. We show that it is possible to probe the effects
of the NMDC on the CMB observables by taking into account both the dynamics of
the inflationary slow-roll phase and the subsequent reheating. We perform a
comparative study between representative inflationary models with canonical
fields minimally coupled to gravity and models with NMDC. We find that the
inflation models with dominant NMDC generically predict a higher reheating
temperature and a different range for the tilt of the scalar perturbation
spectrum $n_s$ and scalar-to-tensor ratio $r$, potentially testable by current
and future CMB experiments.
