Context: Software practitioners are a primary provider of information for field studies in software engineering. Research typically recruits practitioners through some kind of sampling. But sampling may not in itself recruit credible participants. Objectives: To propose and demonstrate a framework for recruiting professional practitioners as credible participants in field studies of software engineering. Method: We review existing guidelines, checklists and other advisory sources on recruiting participants for field studies. We develop a framework, partly based on our prior research and on the research of others. We search for and select three exemplar studies (a case study, an interview study and a survey study) and use those to demonstrate the application of the framework. Results: Whilst existing guidelines etc. recognise the importance of recruiting participants, there is limited guidance on how to recruit the right participants. Our demonstration of the framework with three exemplars shows that at least some members of the research community are aware of the need to carefully recruit participants. Conclusions: The framework provides a new perspective for thinking about the recruitment of credible practitioners for field studies of software engineering. In particular, the framework identifies a number of characteristics not explicitly addressed by existing guidelines.