Allen (heel) didn't participate in Thursday's practice, Daniel Popper of The Athletic reports.
Popper notes that Allen was spotted taking part in agility work and running off to the side with trainers during the open portion of Thursday's practice, but the veteran wideout didn't mix into drills. Allen hasn't logged any practice reps since making his last appearance in the Chargers' Week 14 loss to the Broncos, and at this stage, he appears to be trending toward missing a third straight game this Sunday in a rematch with Denver.