We study the magnetic transition in SrRuO 3 , the only itinerant 4d ferromagnet, employing x-ray absorption fine structure study and state-of-the-art band-structure calculations. Both experimental and theoretical results reveal an unusual evolution of the local structural parameters around the spectator element, Sr, across the magnetic transition. Interestingly, such evolution of the Sr-related bonds nucleate at a temperature, T Ã , higher than the magnetic transition temperature, indicating the presence of a precursor effect. Contrary to common belief, these results point to the active role played by the Sr ion in the magnetostructural coupling present in this compound.