Power Rankings: No. 20 Chargers

A weekly examination of the Chargers’ ESPN.com Power Ranking:

Preseason ranking: 23 | Last Week: 17 | ESPN.com Power Ranking since 2002

The San Diego Chargers dropped three spots to No. 20 in this week’s rankings after losing on the road to Oakland. At 2-3, the Chargers take on one of the hottest teams in the league this week in 4-1 Indianapolis, led by the most talented young quarterback in the NFL in Andrew Luck.

For the Chargers to have a chance to get back to .500, the defense has to play better. San Diego has allowed 25.8 points a contest (No. 19 in the league) and 406 total yards a game (No. 27 in the NFL).

San Diego’s defense is giving up a league-worst 6.51 yards per play, and allowing teams to convert nearly 41 percent of the time on third down, No. 24 in the NFL.

The Chargers face one of the most balanced offenses in the league in Indianapolis. The Colts can pound teams running the ball, averaging 142 rushing yards a contest. But with Luck, Indianapolis also can beat you down the field for big plays in the play-action game.