Previous research suggests that the probability distribution of a word across its inflected variants influences the recognition of that word. Recently, similar effects have been reported for relations between prepositions and definite-noun-phrase heads in English trigrams (e.g., in the bucket). We test whether both effects could be accounted for in terms of string proximity and/or semantic similarity alone, or whether the findings for English trigrams should be attributed to syntactic paradigm effects. We ‘fake’ a case system for English using syntactic positions and prepositions as proxies for the relational meanings expressed inflectionally in other languages. Based on these syntactic factors, we define a syntactic inflectional entropy to parallel the morphological entropy measures used in prior studies. We found that this new measure correlates negatively with visual lexical decision RTs. However, unlike prior studies, we did not find a semantic priming effect between nouns with similar distributions in our paradigmatic vectors.