This aim of this work is to elucidate the impact of the grafted polymer on the flow behavior of sterically-stabilized nanoparticles in homopolymer melts. Specifically, we investigate the rheology of well-characterized dispersions of poly(dimethylsiloxane) (PDMS) grafted silica nanoparticles in PDMS melts. It is well understood that the graft layer must be completely wet by the matrix polymer to achieve uniform colloidal dispersion; however, to date, there is a little fundamental research that systematically investigates the effect of system parameters, such as graft density, matrix chain length and particle size, on bulk properties of grafted particles in polymer melts. Our work examines the degree of stretching of the grafted layer, also called particle “softness”, as a function of molecular weight of the matrix polymer and particle size. We have detected particle interactions for a range of core silica volume fractions with steady state and oscillatory rheological measurements. It is hypothesized that the conformation (i.e. wet-ability) of the grafted polymer has a measurable effect on the bulk rheology as the space occupied by the core and the brush changes. Ultimately, a better understanding of the role of the graft layer on nanoparticles dispersed in polymer melts will aid in optimizing the properties of nanocomposites for applications in biotechnology, optics, catalysis, and plastics.