  Casimir-Polder interactions cause energy and momentum exchange between
microscopic and macroscopic bodies, a process mediated by quantum fluctuations
in the coupled matter-electromagnetic field system. The dynamics of such
effects are yet to be experimentally investigated due to the dominance of
static effects at currently attainable atomic velocities. However, Y. Guo and
Z. Jacob [\textit{Opt. Express}, 22:26193-26202, 2014] have proposed a
non-static two-plate set-up where quantum fluctuation mediated effects have a
strong velocity-dependent resonance, leading to a giant friction force on the
plates. Here a more easily realisable set-up, a moving atom between two
stationary plates, is analysed within a QED framework to establish the
spectroscopic Casimir-Polder effects on the atom, and their velocity
dependence. While no large velocity-dependent enhancement is found, expressions
for the plate-induced spectroscopic effects on the atom were found, and further
shown to be equivalent to the Doppler-shifted static result within certain
velocity constraints. A numerical analysis investigates the behaviour of this
system for the well studied case of the $6D_{3/2}\rightarrow 7P_{1/2}$
transition in $^{133}$Cs interacting with sapphire plates.
