The San Francisco 49ers are legitimate Super Bowl contenders. So are the Green Bay Packers.So the shoulder injury suffered by Green Bay superstar quarterback Aaron Rodgers could be crucial for the 49ers. Initial reports indicate Rodgers may miss three weeks.The impact Rodgers has on the 49ers won't happen until the playoffs. The 49ers are 6-2 and a game and a half behind 8-1 Seattle in the NFC West. Green Bay, which lost to Chicago Monday night after Rodgers was injured early in the game, is in a three-way tie for first place in the NFC North at 5-3.