Three things: Chargers-Cardinals

Three things to watch for Saturday in the Arizona Cardinals' third exhibition of the 2013 season, set for 10 p.m. ET at home against the San Diego Chargers:

1. Whisenhunt homecoming. Former Cardinals coach Ken Whisenhunt returns to University of Phoenix Stadium as offensive coordinator for the Chargers. Will his offense upstage the one his successor, Bruce Arians, has installed with the Cardinals? While this is a silly question in the bigger picture, it's an item of interest in the short term given how little time has passed since Whisenhunt's dismissal in January. Personal subplots abound. Whisenhunt and Arians worked together in Pittsburgh, where Arians succeeded Whisenhunt as the Steelers' offensive coordinator. The history between Whisenhunt, Arians and the Cardinals adds appeal to this matchup.

2. Williams at running back. Third-year running back Ryan Williams returned to practice late in the week and could play against San Diego. He appears to be fighting for a roster spot two years after the team drafted him 38th overall. The Cardinals are averaging 3.0 yards per carry during the preseason. Williams has not played in a game of any kind since Oct. 4, 2012. He has not been the same since suffering a torn patella tendon during the 2011 preseason. Whether Williams plays and how he performs is a leading storyline for Arizona. Either way, Rashard Mendenhall is the starter.

3. Red zone offense. Arians was ticked off after his team settled for four field goals during a 12-7 victory against the Dallas Cowboys at home last week. Finishing drives with touchdowns instead of field goals is always a priority. It's a heightened priority this week. Arizona will be looking for sharper play from quarterback Carson Palmer. Establishing at least the threat of a running game would help, too.