Harris (hamstring) was a non-participant in Thursday's practice.
The Chargers have held Harris out of their first two practices of the week, a development that comes as little surprise after head coach Jim Harbaugh described the wideout as "more week-to-week" than day-to-day coming out of this past Sunday's loss to the Broncos, per Alex Insdorf of BoltBeat.com. Unless Harris is able to make a surprise return to practice Friday, he'll likely miss his first game of the season this Sunday in Kansas City.