Although the Colts finished four games better than the Chargers, many oddsmakers are calling it a pick 'em game, and they should. The Colts may enter as the favorites, but they know it's not a good matchup for them.
The Chargers' 3-4 defense gives the Colts serious problems. The Chargers' defensive line is physical. Their secondary can make plays. The Chargers usually can put pressure on Peyton Manning.
In the 2005 to 2007 seasons, the Chargers won three straight games against the Colts, including last season's 28-24 victory in the divisional playoffs. All three games were close -- the margins of victory were nine, two and four points.
Who can forget the 2007 Sunday night regular-season game in San Diego during which Manning threw six interceptions and let the Chargers build a 23-0 lead? Injuries left the Colts without their starting wide receivers and top tight end, Dallas Clark. But Manning mounted a stirring comeback with street receivers and unknown tight ends whom he barely knew and have long since been forgotten.
In one of his more incredible showings, Manning rallied the Colts with 21 points and had them inside the Chargers' 10-yard line with less than two minutes remaining. All they needed was an Adam Vinatieri field goal to win. But some rare clock mismanagement by the Colts and a miss by Vinatieri gave San Diego a 23-21 victory.
The Chargers came to the RCA Dome as clear underdogs in the second round of last season's playoffs. Tight end Antonio Gates had a toe injury that should have kept him out. Quarterback Philip Rivers played even though his knee needed reconstruction. Confident from their past successes, the Chargers beat the Colts and advanced to the AFC title game.
The Colts squeezed out a 23-20 victory earlier this season in San Diego, but that was an adventure, too. Rivers orchestrated a late-game drive that enabled the Chargers to tie the game and set it up for overtime. But Chargers coach Norv Turner made a fatal mistake when he called a timeout in the final two minutes.
That timeout gave Manning 90 seconds to engineer an eight-play field goal drive to win the game.
The Chargers are confident they can beat the Colts. Both teams are hot. The Chargers have won four straight after a 4-8 start. The Colts have won nine in a row after a 3-4 start.
Saturday's game could be a classic.
Ten more things to watch
1. Lighting up the scoreboard: The first round of the playoffs likely will produce some of the higher-scoring games in the playoffs. The Chargers are the highest-scoring team in the AFC (27.4 ppg.), and the Colts know the only way to slow them is for Manning to possess the ball and keep the Indianapolis defense off the field. The early Saturday game between the Falcons and Cardinals could be a shootout. The Cardinals' defense gives up 26.6 points a game and has a 44.4 percent failure rate on third down. The key for Arizona is finding a way to pressure rookie quarterback Matt Ryan into making mistakes.
Meanwhile, the Dolphins-Ravens game figures to be the best defensive matchup. The Ravens rank second in overall defense and against the pass. The Dolphins are the lowest-scoring first-round playoff team at 21.6 points a game. Their offensive stats aren't great in any category, but they play solid, mistake-free football. The Vikings may not be able to stay with the Eagles if Donovan McNabb gets hot, but Adrian Peterson can break long touchdown runs, and Tarvaris Jackson can come up with some big pass plays.
2. Will there be home-field advantage? Probably not. Some critics of the playoff system are pushing for a reseeding formula, one that NFL traditionalists will never endorse. The critics feel teams' records, not division titles, should dictate the seeding principles. Oddsmakers are giving critics some ammunition. If the Colts end up favored by a point or two in the final line, the road teams will be favored in all four first-round games. The Falcons will be at least two-point favorites over the Cardinals. The Eagles and Ravens are three-point favorites. Bettors are playing the wild-card teams instead of the division winners. That's understandable. The Colts did pull out a three-point victory in San Diego earlier this season. The Ravens went to Miami in Week 7 and smoked the Dolphins 27-13.
3. Colts walking tightrope: Because of their deficiencies on defense, the Colts are forced to play a style that likely will keep the Chargers within a touchdown in the fourth quarter. The Colts have a league-low 150 offensive possessions in 16 games, an average of 9.375 a game. It's hard to score more than 24 points in nine-possession games, although Peyton Manning can get it done.
The Colts' defense gets overpowered against good running teams and gives up chunks of yardage in the passing game. To win, Manning must possess the ball and come up with touchdowns, not field goals. If Manning can put the Colts in the lead by the fourth quarter, the Indianapolis defense will make sacks and force turnovers. But a nine-possession game by the Colts should keep the Chargers, who average 27.4 points per game, within a score of winning or tying.
4. Chargers' secondary concerns: Like the Colts' defense, the Chargers' defense lets quarterbacks stay on the field too long. The Chargers rank next to last in pass defense, allowing 274.4 yards a game. The defense is on the field eight more plays a game than the offense.
Ron Rivera took over for Ted Cottrell as defensive coordinator and fixed a lot of things, but not everything. Rivera has improved the pass rush. He has tightened up some of the problems stopping the run. But the secondary remains a problem. It is vulnerable in the middle of the field. Manning will try to exploit that with Clark.
The Chargers' cornerbacks have been loose with their coverage; when they play tight, they tend to draw penalties. Two turnovers could give Manning an opportunity to put up 14 points in two possessions, a lead that might prove hard for Rivers to overcome.
5. Turner in the crosshairs: Falcons running back Michael Turner will be more of the focus in Saturday's Atlanta-Arizona game than Ryan. Turner was the league's workhorse back with a league-high 376 carries. He finished with 1,699 yards. He had 24 or more carries in seven of the Falcons' final nine games. At that pace against physical defenses, backs tend to wear down. To complicate matters, Turner is dealing with an off-the-field matter. On Monday, police responded to a call from his home after a domestic dispute involving the mother of his child. Although no arrest was made, Turner must persevere through what might be a tough time at home.
The Cardinals will do everything they can to stop Turner and the running game. Adrian Wilson is one of the best safeties in the league playing near the line of scrimmage. The Cardinals give up 110.3 yards a game against the run, but they have blitzing packages that disrupt running attacks behind the line of scrimmage.
6. Do the Cards belong? The Cardinals have to fight through the embarrassment of making the playoffs despite one of the worst finishes in the league. They've lost four of their past six games, including three blowouts. In a 21-point home loss to the Vikings in Week 15, the Cardinals didn't seem to have the maturity to handle their success. Players were uninspired and unmotivated. This is the organization's first home playoff game since 1947, and the Cards need to take advantage of the rare opportunity.
The Cardinals won the NFC West because it is the worst division in football. They were 6-0 against division opponents and 3-7 against the rest of the league. It would help if the Cardinals establish some running offense. Quarterback Kurt Warner has carried Arizona's offense all season.
7. Call of the Wildcat: The Dolphins kept the league off balance with the Wildcat offense, which features running backs taking direct snaps from center and having an extra blocker to help on the run. They ran the Wildcat 90 times for 580 yards and eight touchdowns and were 11-3 in games in which they used their varied forms of the Wildcat. The Ravens stopped the Wildcat in Week 7 (they allowed only 4 yards on five carries), so it will be interesting to see whether the Dolphins can come up with some new wrinkles.
Without the Wildcat, the Dolphins are an average running team. They averaged 6.1 yards a carry using the play but only 3.8 yards per attempt without it. They've also completed two of four passes from the Wildcat. There will be a test of wills on this one.
8. Tale of two QBs: The fascinating matchup in the Ravens-Dolphins game is Joe Flacco versus Chad Pennington, the rookie quarterback versus the seasoned veteran. Flacco has done a remarkable job, winning 11 games as a rookie. The Dolphins opted not to go with a rookie quarterback by passing on Ryan with the first pick in the draft. They were able to get Pennington after he was cut by the Jets. Pennington had a career season, throwing for 3,653 yards and managing an offense that set an NFL record with only 13 turnovers in 16 games. Pennington manages a short passing attack. Flacco runs a play-action attack and occasionally tries to throw deep.
9. Eagles will bring the heat: The key for the Vikings is how QB Jackson handles the blitz. Eagles defensive coordinator Jim Johnson will give Jackson all the blitz looks possible. In his limited play this season, Jackson completed only 43 percent of his passes against the blitz and had one of the worst quarterback ratings in the league when blitzed. Vikings coach Brad Childress has a major weapon in Peterson, however. The best response to a blitz is to gash the defense with a big run.
In Week 17, the Giants blitzed 80 percent of the time against Jackson. Giants defensive coordinator Steve Spagnuolo learned that from Johnson when he spent eight years with the Eagles under Johnson. Expect a lot of blitzes Sunday in the Metrodome.
10. Reid's dilemma: Eagles coach Andy Reid takes constant criticism for not running the ball enough. The Vikings are hard to run against, particularly if defensive tackle Pat Williams comes back from his broken scapula. Williams said he will play. The Vikings are the best run-stopping team in the league, allowing only 76.9 rushing yards a game and only 3.3 yards a carry. Most teams end up abandoning the run against Minnesota, but if Reid comes out throwing the ball on every down, he'll be open to criticism. The Eagles must somehow establish some sort of running game.
John Clayton, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com.