Grain size behaviour during discontinuous dynamic recrystallization in alloys is characterized by a theoretical approach that combines a novel thermostatistics framework, with classical grain nucleation and growth formulations. Configurational effects from dislocation migration paths control microstructure variation via an entropic effect. An alternative approach for accounting for solute-drag effects is proposed. It is shown that the drag atmosphere linearly amounts to the atomic radius of solute atoms. The approach is validated for various deformation conditions in 20 single-phase metals.