Williams saw first-team reps during Tuesday's minicamp while LeSean McCoy sat out due to a stomach virus, BuffaloBills.com reports.
The Bills don't have anyone proven behind McCoy, and Williams -- the team's fifth-rounder in 2016 -- is looking like the clear choice for insurance behind the stud veteran. There's also talk that the Bills will try to take it easy on McCoy around the goal line. If that comes into fruition, guys like Williams and Mike Tolbert could be in line for a share of scoring touches.