Instructional coaching runs the risk of being abandoned by policy makers and secondary schools if efficacy expectations related to adolescent literacy are not met (Knight, 2010; Walpole & McKenna, 2008). Research into coaching has examined the roles of coaches (Borman & Fenger, 2006; Smith, 2007) as well as the stances employed during collaborations (Costa & Garmston, 2002; Deussen et al., 2007; Ippolito, 2010), but insufficient research has explored how secondary coaches attempt to impact adolescent literacy in unfamiliar disciplines and the ways instructional coaches use coaching practices to negotiate disciplinary tensions. This paper is part of a larger qualitative study aimed at investigating the "heavy coaching" (Killion, 2009; 2010) discourse and practices employed by coaches at three different secondary schools as they attempted to improve the disciplinary literacy of students. In this paper, I present the case study of Eric, a former high school English teacher, as he worked with a high school algebra teacher, Jackie, over the course of a semester. While Eric attempted to coach heavy, the disciplinary tensions prompted him to employ situated coaching practices. Findings from this study suggest a disciplinary outsider status may be ameliorated through a coach's use of transparency and collaborative practitioner inquiry.