Square (undisclosed) passed a physical Friday, spurring the Chargers to activate him from the active/non-football injury list, per the NFL's transaction log.
After spending less than a week on the list, Square was able to prove his health and join his teammates for the strength and conditioning part of training camp. The 31-year-old notched 27 tackles and two pass deflections as a member of the Chargers' defensive tackle rotation last season.