The authors developed the practicum-based microteaching model based on the notion of 'approximations of practice' to explore how the concept provides meaningful opportunities for preservice teachers' teacher learning in a general secondary methods course. The results reveal that the practicum-based microteaching model provided preservice teachers with opportunities for interactive learning practices, for rehearsal, revision, and retrial, and for manageable chunking of professional practices. Moreover, this study also found that preservice teachers well accepted the learning tasks such as planning and teaching a microlesson as manageable chunks of professional practices in teacher education.