Head coach Jim Harbaugh told reporters Wednesday that Colson's placement on the active/non-football illness list is due to an appendectomy, Eric Smith of the Chargers' official site reports.
Chargers head coach Jim Harbaugh said that Edwards (undisclosed) went through individual drills during Wednesday's practice, Kris Rhim of ESPN.com reports.
Spiller is slated to compete with rookie sixth-round pick Kimani Vidal for the No. 3 running back job behind Gus Edwards (undisclosed) and J.K. Dobbins (Achilles) during training camp, Alexander Insdorf of BoltBeat.com reports.