Writing researchers have suggested that students who are perceived as strong writers (i.e., those who generate texts that are rated as high quality) demonstrate flexibility in their writing style. While anecdotally this has been a commonly held belief among researchers, scientists, and educators, there is little empirical research to support this claim. This study investigates this hypothesis by examining how students vary in their use of linguistic features across 16 prompt-based essays. Forty-five high school students wrote 16 essays across 8 sessions within an Automated Writing Evaluation (AWE) system. Natural language processing (NLP) techniques and Entropy analyses were used to calculate how rigid or flexible students were in their use of narrative linguistic features over time and how this trait related to individual differences in literacy ability and essay quality. Additional analyses indicated that NLP and Entropy reliably detected narrative flexibility (or rigidity) after session 2 and was related to students' prior literacy skills. These exploratory methodologies are important for researchers and educators, as they indicate that writing flexibility is indeed a trait of strong writers and can be detected rather quickly using the combination of textual features and dynamic analyses.