The primary objectives of the study are: To determine the mass balance and routes of elimination of BIIB074 and its known metabolites following administration of a single oral dose of BIIB074 in healthy male participants and To describe the pharmacokinetics (PK) of BIIB074 and its known metabolites and the disposition profiles of total radioactivity in whole blood and plasma following a single oral dose. The secondary objectives of this study are: To assess the safety and tolerability of BIIB074 in healthy participants and To identify and characterize any additional metabolites of BIIB074 in plasma, urine, and feces.