Everybody knows the 49ers can stop the run. But it's been a different story so far this season when they go up against a Pro Bowl passer. Tony Romo and Michael Vick shredded San Francisco through the air in the Niners' two closest games this season, and with Eli Manning coming to town this week, the back end of the NFL's No. 1 rushing defense will get another test against a top-shelf quarterback.