Inertial migration of a neutrally buoyant rigid sphere in circular Poiseuille flow is strongly affected by particle rotation, yet its role remains poorly understood. This study employs three-dimensional fully-resolved CFD-DEM simulations to investigate inertial migration with and without particle rotation. The model is validated against experimental equilibrium radial positions. Simulation results reveal that suppressing rotation consistently shifts the equilibrium radial position toward the pipe centerline, but rotation's effect on the migration dynamics depends on the sphere's initial radial position. When rotation is suppressed, radial migration accelerates for the sphere released near the pipe wall, whereas radial migration slows for the sphere released closer to the centerline. While the freely rotating spheres experience a transition between different migration regimes as the sphere-to-pipe diameter ratio or the fluid Reynolds number increases, non-rotating spheres remain in the monotonic regime since they stabilize closer to the pipe centerline where both shear-gradient and wall-induced lift forces vanish. Moreover, suppressing rotation increases the entry length required for the sphere to achieve full migration. This study elucidates how particle rotation affects inertial migration and offers new insights into rotation-modulated lateral migration in microfluidics.