Allen isn't participating in the portion of Wednesday's practice open to the media, Eric D. Williams of ESPN.com reports.
The Chargers never actually reported an injury, but Allen did appear to be limping at one point in Sunday's 35-23 loss to the Rams, ultimately playing just 77 percent of the offensive snaps after logging a 88 and 89 percent share during the first two weeks of the season. Another update will be available when the Chargers release their first injury report of the week.