In cosmological models where dark energy has a dynamical origin one would expect that a primordial inflationary epoch leaves no imprint on the behavior of dark energy near the present epoch. We show that a notable exception to this behavior is provided by a nonlocal infrared modification of General Relativity, the so-called RT model. It has been previously shown that this model fits the cosmological data with an accuracy comparable to \Lambda CDM, with the same number of free parameters. Here we show that in this model the dark energy equation of state (EOS) near the present epoch is significantly affected by the existence of an epoch of primordial inflation. A smoking-gun signature of the model is a well-defined prediction for the dark energy EOS, w_{\rm DE}(z), evolving with redshift from a non-phantom to a phantom behavior, with deviations from −1 already very close to the limits excluded by the Planck 2015 data. Future missions such as Euclid should be able to clearly confirm or disprove this prediction.
