In this paper numerical simulations of particle migration in lubricating grease flow is  presented. The rheology of three lithium greases with NLGI grade 00, 1, and 2 respectively are  considered. The grease is modeled as a single-phase Herschel-Bulkley fluid, and the particle  migration has been considered in two different grease pockets formed between two concentric  cylinders where the inner cylinder is rotating and driving the flow. In the wide grease pocket the  width of the gap is much smaller compared to the axial length scale, enabling a one-dimensional  flow. In the narrow pocket the axial- and radial length is of the same order, yielding a  three-dimensional flow. It was found that the change in flow characteristics due to the influence of  the pocket lateral boundaries when going from the wide- to the narrow pocket, leads to a  significantly shorter migration time. Comparing the results with an existing migration model  treating the radial component contribution it was concluded that a solution to the flow in the whole  domain is needed together with a higher order numerical scheme to obtain a full solution to the  particle migration. This is more pronounced in the narrow pocket due to gradients in the flow  induced by the lateral boundaries.