Both DoD and service specific mandates call for Human Systems Integration (HSI) to be addressed throughout all phases of the System Acquisition (SA) process. While HSI domains and their associated methods and tools are well defined, there does not exist corresponding strategic or practical guidance for Program Managers (PMs) as to when in the acquisition process different types of HSI methods and tools have application. Absent such a road map, PMs often rely exclusively on experience without a basis for prioritizing cost, benefit, and data availability. A framework is presented for organizing the strategic application of different classes of HSI methods and tools, specifically those related to Manpower, Personnel, Training, and Human Factors Engineering. This framework is predicated on the idea that there are a finite set of SA strategies or use cases for material solutions--it is salient aspects of the SA strategy that should drive the tactical application of HSI methods and tools. It is argued that rather than defining one process that dictates when different types of HSI methods and tools should be applied, it is more useful to view the SA strategy as informing the application of methods and tools in terms of a constraint satisfaction. An approach to understanding and prioritizing constraints is presented and then using this knowledge, a framework for application of different types of HSI methods and tools is outlined. Example SA strategies are detailed and the framework is applied to provide examples of when in the SA process different types of methods and tools should be applied, what their input requirements would be, what their output would be, and which SA artifacts these categories of methods and tools inform.