None of the starters have played for the Chargers. The 49ers played their offensive starters for one series, and predictably dominated the Chargers' backup defense.
I find it interesting that D.J. Smith got the start at linebacker over Bront Bird, which probably makes him the favorite to start at that position against the Houston Texans in week one.
Also, Rich Ohrnberger, who can play both center and guard, got the start at center over David Molk, putting Molk on watch for getting cut on Saturday.
As far as "on the bubble" players that have probably secured their place on the roster on Saturday, Jahleel Addae is the only one that has stood out, with a highlight hit to stop a run at the line of scrimmage.
Brad Sorensen is expected to be the San Diego QB at the start of the third quarter, so there should be plenty for us to watch and more highlights to come in the second half from the Chargers backups backups.