Contributions to Spanish historical morphology are used to dealing with many descriptive issues, but they generally lack methodological considerations. This was not the case with other components of historical grammar such as the phonological and the lexical ones. However morphology, perhaps because of its semiproductive character and the irregularity of its paradigms, has been conceived of as a sample of unrelated data. This paper aims to consider the paradigmatic proposals that have been recently made by Joel Rini putting them in the methodological context of current research on grammaticalization in general linguistics.