Douglas (undisclosed) exited Monday's practice early, David Furones of the South Florida Sun Sentinel reports.
The rookie was seen walking off with trainers during Monday's session but later returned to the sidelines, at which point his day was done from a participation standpoint. The exact nature of Douglas' issue is unclear at this point, but his ability to return to practice this week will settle that. Douglas is one of several young Dolphins looking to make a splash in a revamped receiver room this season.