As many of current ecological and social challenges are understood to be particularly persistent, deep-rooted and systemic, remedial strategies are proposed that are of a likewise systemic orientation. As the requisite system transformations may offer solace only when it's too late however, the crucial task for transitions governance may therefore be to ensure acceleration. This contribution brings forward a critical perspective on this issue. Against the all too linear ‘race track' metaphor introduced by acceleration ambitions, it is aimed to explore and specify the governance challenges of transitions, and especially the governance of transformative social innovation (TSI). As will be argued through a dialectical perspective, such processes crucially unfold through the collective struggles and negotiations between diverse actors and institutional logics. Initiatives towards transformative social innovation are subject to translation and capture: This will be illustrated through the exemplary case of the Social Solidarity Economy (SSE), and the practice of ‘insertion' in particular. The paper concludes by teasing out the main empirical observations on capture dynamics, and by reflecting on their wider implications for the governance of transitions and transformative social innovation.