  Based upon the kinematics of ten globular clusters, it has recently been
claimed that the ultra-diffuse galaxy, NCD 1052-DF2, lacks a significant
quantity of dark matter. Dynamical analyses have generally assumed that this
galaxy is pressure supported, with the relatively small velocity dispersion of
the globular cluster population indicating the deficit of dark matter. However,
the presence of a significant rotation of the globular cluster population could
substantially modify this conclusion. Here we present the discovery of such a
signature of rotation in the kinematics of NGC 1052-DF2's globular clusters,
with a velocity amplitude of $\sim12.44^{+4.40}_{-5.16}$ km/s, which, through
Bayesian model comparison, represents a marginally better fit to the available
kinematic data; note that this rotation is distinct from, and approximately
perpendicular to, the recently identified rotation of the stellar component of
NGC 1052-DF2. Assuming this truly represents an underlying rotation, it is
shown that the determined mass depends upon the inclination of the rotational
component and, with a moderate inclination, the resultant mass to light ratio
can exceed $M/L\sim10$.
