I said it last year, during his rookie season, and I've been saying it again this year: Andrew Luck is underrated. He might be the best pure quarterback in the entire league. He can do absolutely anything (throw deep, throw short, run, throw on the run, and everything is accurate) and he's as close to unflappable as I've seen from a second-year player.
It's no coincidence that this Colts team went from 10-6 with Peyton Manning, to 2-14 without Manning, to 11-5 with Andrew Luck. There are a lot of gaps in talent on this roster that Manning made up for, and Luck is doing the same. The offensive line isn't great, but Luck is so athletic that it doesn't matter. The receivers aren't spectacular, but Luck makes them look like they are.
The Colts can sometimes get off to slow starts in games, playing down to a lot of their competition early, before Luck takes over in the fourth quarter with relative ease. There's really no way to "beat" Andrew Luck, you just have to hope for an off day and maybe a lucky bounce (or three).
The Running Game
Pep Hamilton left the Stanford Cardinal this offseason to reunite with former pupil Andrew Luck in Indianapolis. A lot of people see it as an opportunity to ride Luck's coattails to a shot as an NFL Head Coach, and it is undoubtedly that, but don't disregard how good (and stubborn) Hamilton is at calling plays.
The Colts were the 18th best offense in 2012, according to DVOA. They were 18th best at running the ball and the 21st best team at passing the ball under Bruce Arians. This season, they are the 4th best offense according to DVOA. Their passing game is 10th best and their running game is 2nd best in the league.
So, what changed? Well, an insane dedication to offensive balance. The 2012 Colts threw the ball 628 times and ran it 440 times. The 2013 Colts have thrown it 159 times and run it 151 times. When Vick Ballard went down for the season with a knee injury, Indy traded a draft pick to the Cleveland Browns for Trent Richardson so that they could keep running it as much as they throw it.
The Colts have arguably the best young quarterback in the league, and Pep Hamilton still centers everything around the ground game. Runs are used to set up the pass, and passes are used to set up the run. The Colts run on passing downs and throw on running downs, just to keep opposing defenses off balance. There do not appear to be any tendencies of this Colts offense, except that they have the skill to run any play effectively and will do so at any time. Imagine game-planning against that.
A Perfect Defense
You would think, with as good as their offense is, that the Colts wouldn't be very strong on defense. You'd be half-right. Chuck Pagano's defense is missing a Haloti Ngata-like anchor in the middle, so they struggle to slow down opponents' running games and mobile quarterbacks (Russell Wilson, Terelle Pryor) can get big plays against them as well. That's the good news. The bad news is that their pass coverage is really good, as is their pass rush. Robert Mathis has an insane 9.5 sacks through five games.
The San Diego Chargers rushing game hasn't been very impressive this season. In fact, it's ranked 22nd in the league according to DVOA (despite the passing offense being ranked 2nd in the league). Ryan Mathews is banged up in more than one way, and there are no real alternatives in terms of a starting running back on the roster. It will be difficult for San Diego to take advantage of Indianapolis' weak middle.
This truly will be a matchup of strength of strength when the Chargers have the ball. Will Philip Rivers and the high-flying passing game be good enough to top the league's 7th best pass defense? Will King Dunlap (if he plays) be able to slow down Robert Mathis?