The current debate in second language acquisition and heritage language learning is no longer about whether communicative language teaching should include a focus on form, but rather "how" and "when" this is most effective. The proposals for Spanish for heritage language learners (HLLs) courses show a marked preference for an integrated approach to syllabus design, such as content-based and community-based courses. In this article, I explore on theoretical grounds the suitability of Ellis's (2002) modular approach to syllabus design in developing Spanish for HLLs syllabi as an alternative to the integrated syllabus. I explain how some of the limitations of the integrated syllabus are even greater in Spanish for HLLs courses. I also provide a rationale for the implementation of a modular approach, based on two fundamental properties: 1) a place for isolated form focused instruction (FFI) and 2) the specific timing in which this isolated FFI is introduced. I argue here that the type of target features that need to be (re)acquired by HLLs, as well as the characteristics of the HLLs, make the presence of a component for isolated FFI particularly beneficial for Spanish for HLLs courses. (Contains 7 notes and 1 figure.)