San Diego at Indianapolis
Time: Sunday, 1 p.m. ET

Players to watch
Chargers

Getty Images Chargers quarterback Philip Rivers.

The one thing the Chargers don’t want to do is turn this into a mano-a-mano between their quarterback, Philip Rivers and the Colts’ Peyton Manning. That means the critical offensive player for San Diego will be running back LaDainian Tomlinson. Rivers’ favorite receiver, tight end Antonio Gates, was hurt in the wild-card win over Tennessee, and if he can’t go, Tomlinson will play an even bigger role in the passing game. Watch Chris Chambers, the receiver obtained from Miami in midseason; he’s been a big part of the team’s success. On special teams, Darren Sproles has the ability to change a game with a big return. Defensively, this is a team that led the league in turnovers forced. Shawne Merriman is a monster at linebacker and cornerback Antonio Cromartie is going to have to come up big against the Colts great receivers. If it’s close, kicker Nate Kaeding is one of the best.

Colts
This is Peyton Manning’s team, and the Colts are still the defending Super Bowl champions. He’s finally got future hall-of-fame receiver Marvin Harrison back, which will really open up the field for fellow wideout Reggie Wayne. Dallas Clark is a great target at tight end. The Colts rely on running back Joseph Addai to keep defenses honest. But it’s the defense that has really shined this year, ranking first in points allowed and third in yards allowed. The key to that defense is safety Bob Sanders, who hits as hard as anyone in the league. Defensive end Robert Mathis leads the pass rush.

The Chargers win if
San Diego has to play pretty much a perfect game offensively — no turnovers. On defense, they’ve got to get at least two takeaways, including one that goes for a touchdown. Another big play from Sproles on special teams could result in a huge upset.

The Colts win if

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Just keep doing what they’ve been doing: gang up on Tomlinson on defense and let Rivers try to beat them — and he'll inevitably give the ball away. On offense, protect Manning and let Harrison and Wayne do the rest.

The Chargers lose if
Lose the turnover battle, don’t pressure Manning, fail to contain Addai. That will pretty much spell for San Diego what it’s spelled for everyone else for several years now — defeat.

The Colts lose if

Stephen Dunn / Getty Images Colts quarterback Peyton Manning.

Indianapolis can’t let San Diego shorten the game by hammering Tomlinson and eating up clock with long drives primarily on the ground. If Tomlinson finishes the game with about 150 yards, it will mean the Colts have lost.

Prediction
It’s hard to see how San Diego, as good as their defense is, can outgun the Colts, who are playoff hardened and defending their Super Bowl crown. The Colts are comfortable playing tight relatively low-scoring games, and they’ll do that against San Diego. Sanders will be huge in bottling up Tomlinson, and Rivers will commit several critical errors, sending the Colts to an AFC Championship showdown against the Patriots. Colts 20, Chargers 10.