It is a well accepted point of view that the flow of amorphous media is realized via local plastic events that correspond to small rearrangements in the disordered structure. When such materials are actively deformed, the local plastic events will organize into avalanches, that span the whole system in the limit of small strain rates. In this talk I will describe how this cooperative behavior influences diffusion in the sheared material and I will show a direct relation between the diffusion coefficient and the dynamical susceptibility. Considering experiments this means that the measure of the often more easily accessible diffusion coefficient of tracer particles in a sheared disordered material can provide detailed inside into its microscopic rheology.