After a shift in upper elementary reading instruction that emphasized complex learning using nonfiction text, Texas schools showed low reading comprehension scores among upper elementary students. The purpose of this exploratory single case study was to examine the pedagogical content knowledge of Texas upper elementary teachers who teach nonfiction reading comprehension strategies to at-risk students who do not qualify for special education services. The central research question focused on how teachers view their pedagogical content knowledge while instructing students. The conceptual framework for this study was a combined Shulman's (1986) pedagogical content knowledge model and Thomlinson's (2000) differentiated instruction learning model. Data sources included online questionnaires (N=161), open-ended scenario-based phone or Skype interviews (N=10), and public documents on reading professional development in the state of Texas. Findings from open coding and inductive analysis indicated that the paradigm shift from reading to learn to learning to read is a challenge in the upper elementary classroom, teachers are relying on inadequate professional development to develop their pedagogy and content knowledge, and teachers may be rescuing struggling students rather than differentiating them. Findings may help Texas educators make more informed decisions on pedagogy to promote expository reading comprehension among upper elementary at-risk students and to increase their opportunities for success.