Background: Game-centred approaches (GCA) have been promoted as a more meaningful way to teach games and sports due to their connections with constructivist learning principles. However, the implementation is dependant on the teacher implementing it rather than just the model. There has been little research into what it means to use a GCA well and make judgements in relation to this. Purpose: The paper will focus on presenting the conceptualisation and development of the GCA assessment tool and demonstrating its use in action. Participants: The participants are third-year students in their fourth of five practical studies' courses in games and sports. Data collection: Data were collected during GCA lessons for fellow students in net court category. The exchanges were recorded on an iPod and categorised into "Emerging", "Developing" and "Developed" levels of use, based on aligning key characteristics of GCAs with principles evident in constructivist learning environments. Intervention: Physical education teacher educator (PETE) undergraduates were required to teach a mini lesson using a GCA in the fourth of five practical studies' courses and assessed using a systematic assessment tool that allowed judgements to be made in relation to levels of use. Research design: To understand how GCAs vary in use, an ethnomethodological approach was used. This allowed the author to demonstrate how the Scaffold was developed and used in practice. Data analysis: The data were analysed by the GCA Assessment Scaffold and used to show how this systematic assessment of GCA features and constructivist learning principles can be used in practice. Findings: The study examines the development and practical application of the GCA Assessment Scaffold in practice. It demonstrates that GCA lessons are reliant on the teacher using the model, not just the model and shows that lessons that have all of the features of GCA can either produce high quality-learning outcomes or shallow, depending on the teacher. Conclusion: The paper aims to begin a conversation on both how to assess GCA and how a further development of this tool can improve teaching practices in GCA and other constructivist teaching strategies.