LaDainian Tomlinson's backup, Darren Sproles, had 328 all-purpose yards in the Chargers' first-round win over the Colts. (By Harry How -- Getty Images)

Offense

San Diego has been explosive at times, especially when RB LaDainian Tomlinson was healthy. But his groin injury may be bad enough to keep him out of the game. Backup Darren Sproles is an effective scatback who had 328 all-purpose yards in last week’s win against Indianapolis. To win, Chargers QB Phillip Rivers must have a big game. ..... The Steelers must be able to run to be effective. QB Ben Roethlisberger, recovering from a concussion two weeks ago, will be pressured, and that could be a problem given the weakness of the offensive line.

Defense

Though the Chargers have won most of their games by wide margins, they do have a solid defense that has recovered from the loss of LB Shawne Merriman early in the season. San Diego has a physical front that could cut down Pittsburgh’s running game. ..... The Steelers have a dominant defense that will pressure Rivers constantly. LB James Harrison, with his 16 sacks and seven forced fumbles, could be a huge factor as could S Troy Polamalu, with his seven interceptions.

Special Teams

San Diego has the advantage here. P Mike Scifres almost single-handedly kept the Chargers in the game last week against Indianapolis with booming punts and gently dropped kicks inside the 5-yard line. Sproles is a dangerous returner and a threat to break open a touchdown at any time. If he has to carry the ball a lot in Tomlinson’s place, his effectiveness on returns could be hampered.

Coaching

The Chargers’ Norv Turner has been much maligned over the years but has now won three of four playoff games with San Diego. His reputation as an offensive genius may be tested this week, however. ..... Pittsburgh’s Mike Tomlin has won division titles in both of his years as the Steelers’ coach and has quickly built a reputation for a patient but tough style.

Winner: San Diego.