This pilot study investigated the attitudes of preservice teachers at a major university in Arizona concerning the Structured English Immersion (SEI) program that is now being used with English language learners (ELLs). Using a survey, we examined how preservice teachers feel about potentially working with ELLs in this SEI context. We focused on their beliefs about language teaching and learning, including their perceived level of preparation to work with ELLs, their attitudes toward them, and the difficulties they anticipate in teaching ELLs in the future. The results show that preservice teachers lack some of the fundamental knowledge necessary to work with ELLs, and they highlight the importance of incorporating the insights of the larger TESOL field into K-12 teacher-training programs. We argue that K-12 teacher-training programs, especially in states with English-only policies, may be serving to marginalize the TESOL profession and the contributions it may provide to the education of ELLs.