On their first possession of the second half this past Sunday, the Chicago Bears found themselves at the Packers' 30-yard line after a great punt return by Devin Hester.Immediately, they pounded on Green Bay's greatest weakness: its run defense.On Play No. 1, Matt Forte ran up the middle for 15 yards. Next, it was Forte around left end for 3 yards. On Play No. 3, Forte went off right guard for 4 yards. Play No. 4 was a 3-yard gain around left end. And, on the fifth play of the drive, Forte crashed off left tackle for 5 yards and a touchdown. Five plays, five runs.Though the Packers would go on to win the game, 33-28, Forte rushed for 110 yards and two touchdowns. It was just more of the same for Green Bay's defense in a season in which the Pack has been almost powerless to stop opponents from running the ball – especially without star linebacker Clay Matthews, who'll again miss this Sunday's playoff game against the 49ers at Lambeau Field.The Packers will be trying to stop a San Francisco offense that thrives on running the football. It will be strength (the 49ers' third-best rushing attack) against weakness (the Packers' 25th-ranked rushing defense).As Eric Branch of the...