McCoy said there is no specific timetable for Allen’s return.
Allen left Sunday’s 29–26 loss against the Baltimore Ravens with muscle spasms after catching a 13-yard touchdown in the corner of the end zone just before halftime. Allen appeared shaken up after the play and did not return. Before he left the game, Allen had five catches for 35 yards.
Allen, 23, ranks second in the league with 67 receptions and third with 725 receiving yards this season.
The third-year player out of California broke his collarbone and dealt with an ankle injury last season.
Dontrelle Inman is listed behind Allen on the Chargers depth chart.
The Chargers (2–6) play the Chicago Bears (2–5) at home next Monday night.