  The usual scenario of ``eternal inflation'' involves an approximately de
Sitter spacetime undergoing upward fluctuations of the local expansion rate
$H$. This spacetime requires frequent violations of the Null Energy Condition
(NEC). We investigate the fluctuations of the energy-momentum tensor of the
scalar field in de Sitter space as a possible source of such violations. We
find that fluctuations of the energy-momentum tensor smeared in space and time
are well-defined and may provide the NEC violations. Our results for slow-roll
inflation are consistent with the standard calculations of inflationary density
fluctuations. In the diffusive regime where quantum fluctuations dominate the
slow-roll evolution, the magnitude of smeared energy-momentum tensor
fluctuations is large enough to create frequent NEC violations.
