SAN DIEGO -- The Indianapolis Colts travel to the West Coast for the second time in four weeks after an impressive win at home against Seattle. The last time the Colts traveled to California, they thumped last year's NFC champions, the San Francisco 49ers, 27-7 on Sept. 22.

Indianapolis quarterback Andrew Luck is showing no signs of slowing down in his second season. But he'll face a veteran signal caller in San Diego's Philip Rivers, who is playing back at an elite level after a rough, two-year stretch.

ESPN.com Chargers reporter Eric D. Williams and Colts reporter Mike Wells break down the matchup:

Williams: The national expectation heading into this season was that last year's 11-5 playoff team was a mirage, and the Colts would slide back to .500 this year. That, of course, has not happened, with Indianapolis beating up on NFC West powers San Francisco and Seattle on its way to a 4-1 record. Besides Andrew Luck's impressive play, what has been the key to the Colts' success this season?

Wells: You can't put it on one player. If you had to pick one organization that's truly a team, you have to look at Indianapolis. Luck is obviously the franchise player, but he's not carrying the offense. The Colts are fourth in the league in rushing and 24th in the league in passing. Nobody would have ever thought that would happen with Luck taking the snaps. You also can't forget about the defense. That unit is 11th in total defense and is only giving up 15.8 points a game. So, credit goes to all areas, including the coaching staff. The same can't be said about the Chargers, it seems. They're sitting at the bottom of the AFC West. What's been their biggest issue this season?

Williams: Inconsistency. The Chargers play impressively one game, but look sluggish the following week, which is the reason the team is 2-3. In his first season, San Diego coach Mike McCoy's squad has been competitive in all five games. However, the Chargers have had trouble finishing in the final quarter. The Chargers just came out flat against Oakland last week, falling behind 17-0 before rallying in the fourth quarter to make the game close. Good teams play at a high level each week, and San Diego is still working toward that goal. Mike, you mentioned the Colts' surprising ability to effectively run the ball this season. How has the trade for Trent Richardson helped in that effort?

Wells: I wrote earlier this week that general manager Ryan Grigson should be getting Executive of the Year votes already, despite it only being Week 6 of the season. It cost the Colts a first-round pick, but acquiring Richardson was an excellent move by Grigson, considering they've lost two starting running backs -- Vick Ballard and Ahmad Bradshaw -- already. Richardson's progress with the Colts has been slow. You can tell he's not completely comfortable yet. He had an impressive second half against the team you used to cover -- Seattle -- rushing for 54 yards on 12 carries. The hope within the organization is Richardson will be able to build off that game. Quarterback Philip Rivers has completed 72 percent of his pass attempts in three meetings against the Colts. He's fourth in the league in passing this season. Can the Chargers continue to build around him?

Williams: At present, that's the plan. A year ago, you could certainly argue that Rivers was on the downside of his career. He had 47 turnovers through the 2011 and 2012 seasons, second-most in the NFL. But Rivers experienced a rebirth in McCoy's up-tempo offense. As you mentioned, he's fourth in the NFL in passing yards (1,610), second in passing touchdowns (13) and second in completion percentage (73.8 percent) -- proving at 31 years old there's still some tread left on the tires. Tight end Antonio Gates is healthy and again playing at a high level. Danny Woodhead gives them a high-effort guy who can make plays in the passing game out of the backfield. Young receivers Keenan Allen and Vincent Brown are making plays and earning Rivers' trust. Other than consistently running the ball, San Diego is clicking on offense. But the defense is a different matter. Speaking of defense, you mention the Colts are 11th in total defense. Indianapolis also has forced 10 turnovers, including seven interceptions. The Colts forced just 15 turnovers all of last season. What's changed?

Wells: The players are finally comfortable with coach Chuck Pagano's 3-4 defensive scheme after spending most of last season getting used to it. Robert Mathis went from playing defensive lineman to being a rushing linebacker. Now he's leading the league in sacks with 9.5 to add to his two forced fumbles. The Colts also have seven interceptions. Cornerbacks Vontae Davis and Greg Toler are both players who enjoy being aggressive in going after the ball. It started in training camp and it's carried over to the regular season. They'll lose some battles by gambling to make a play, but they've won the majority of their battles this season. Barring a sudden collapse, the Colts are in a good position to win the AFC South and make the playoffs. How realistic is it for the Chargers to be a playoff team?

Williams: With two undefeated teams leading the AFC West in Denver and Kansas City at 5-0, you would think the Chargers are a long shot to make the playoffs at 2-3. However, if the playoffs were to start today, San Diego would be only a game off the pace for the final AFC wild-card spot. The Chargers still have two games remaining with both the Broncos and Chiefs, along with a home contest against the Raiders in the second half of the season. It's certainly an uphill climb for San Diego to get into postseason contention, but it's doable if they take care of business at home and sneak a couple of wins on the road. Hard to believe we've gone this far without talking specifically about Luck, but how has he improved from his rookie season to this year?

Wells: This might be a record for how many questions I've gone without talking about Luck in Double Coverage this season. He's improved in all areas, which was expected because he's his own worst critic. You talk to him after a game or during the week, and instead of talking about what he's doing well, he usually points out what areas he needs to improve. You like to hear that because that means he's not getting too full of himself. Luck likely won't pass for as many yards this season, but he's OK with that because the Colts are running the ball so well. One area Luck needs to improve in, though, is learning how to slide. Let's just say you won't see him pop up on any tutorials on how quarterbacks should slide. Speaking of waiting so long to talk about a familiar name, how's linebacker Manti Te'o coming along? I have to ask since he's a Notre Dame product.

Williams: Te'o has a total of eight tackles in two games, after sitting out the first three games of the season with a sprained foot suffered in August. Te'o admitted that he's been tentative and thinking too much on the field. Because of that, he's not made any of the game-changing type of plays that he became known for at Notre Dame. Also, the Chargers have worked him in slowly. Te'o played just 14 snaps his first game and 42 snaps last week against the Raiders. He's a hard worker and serious about his craft, so I expect his play to improve over time. Luck has one of the more underrated receiving units in the NFL with wide receivers Reggie Wayne and T.Y. Hilton, along with fellow Stanford-product, tight end Coby Fleener. Wayne, 34, doesn't appear to be slowing down, while Hilton and Fleener are two emerging, young talents. How does that trio work with Luck to create explosive plays in the passing game?

Wells: Wayne is Mr. Reliable for Luck. He's always going to come through when his quarterback needs to come up with a play. Hilton is Luck's deep threat. The two connected for two touchdown passes, including a career long of 73 yards for both players, against Seattle last weekend. In fact, Hilton has outplayed Darrius Heyward-Bey, who is the team's No. 2 receiver, all season. You probably forgot Heyward-Bey is even on the roster. Fleener hit a rough stretch during training camp, but he's been solid for the most part. He's had to play an increased role because fellow tight end Dwayne Allen is out for the season with a hip injury. I see Gates is leading the Chargers in receiving. Are there any signs of him slowing down?

Williams: Gates has struggled with foot and rib injuries the past few seasons, but is finally healthy and back to playing at a high level. As you mentioned, he leads the team in receiving with 32 receptions for 438 yards and three touchdowns. Among tight ends, Gates is second in the league in receptions behind Jimmy Graham (37). At 33 years old, Gates still has enough juice to get deep, and the former Kent State college basketball player remains a matchup nightmare in the red zone.

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