Increasingly, researchers in human resource management are recognizing the impact of relational characteristics of work design on performance outcomes. In particular, complex task interdependencies associated with loosely structured teams call for an approach to work design that incorporates interpersonal relationships and informal communication to help individuals adapt to changing demands. Taking a social network perspective, we propose that position in the structure of informal communication networks shapes the opportunities and constraints to action for individuals and determines their informal roles. We present a multilevel model in which the relationship between position within a social structure and individual performance was examined within the context of team performance and team tenure. Hypotheses were tested using network data collected from nearly 300 employees in 30 sales teams. Results indicated that individuals close to the core of a team outperformed more peripheral individuals, but only to the extent that teams were high-performing or had been together longer as a team. The article concludes with a general discussion of the implications for HR theory and practices targeted at improving individual performance outcomes. © 2013 Wiley Periodicals, Inc.