Several positive effects of the use of games in classroom teaching have been reported. However, in order to make game-based learning effective, teachers' current practices, their concerns and support mechanisms need to be better understood. This study collected data through an online survey from almost 1300 Estonian teachers about their game use and used the Concerns Based Adoption Model (C-BAM), more specifically the Stages of Concerns Questionnaire (SoCQ), to derive profiles of teachers' practices in the adoption of games. We applied descriptive, inferential and multivariate statistics to establish the characteristics of those teachers using games, their teaching practices, challenges, and support they drew on. As C-BAM suggests, the profiles we found represent stages of adoption, from lack of time and interest, to lack of time, to being halfway there, to experimenters and mature users. These clusters of teachers show different behaviours, and express different needs and expectations with regards to game use. Patterns of use in higher adoption stages show a more meaningful integration of games in teaching as they develop their practices. Our results highlight that depending on the stage of adoption, support mechanisms have different potential to contribute to meaningful use of games, and generally getting inspiration from others, sharing ideas and training are the most important factors for teachers.