  We present the calculation of the leading contribution to the quark Sivers
function at small-Bjorken $x$. This calculation uses the high energy scattering
approximation and operator formalism developed by Kovchegov and Sievert to
obtain a dominant contribution to the quark Sivers function coming from the
spin-dependent odderon, in agreement with the results of Dong, Zhen, and Zhou.
We then calculate this dominant contribution in the diquark model of the proton
to obtain a small-$x$ estimate for the Sivers function.
