Traumatic brain injury (TBI) is a leading cause of disability in adults. More sophisticated methods are required in order to understand its underlying pathophysiology and disease progression. Recent interest in an assumption-free DTI analysis, diffusion entropy (DE), has produced some promising results for investigating white matter (WM) and grey matter (GM) microstructure. We set out to test DE against the much more common fractional anisotropy (FA) analysis, in both WM and GM, in 45 hockey players over one season. 11 players sustained a concussion and were scanned at 72 hours, 2 weeks, and 2 months post-injury.