49ers vs. Bears: Is Michael Bush or Matt Forte the bigger concern?

Over the last four weeks, the 49ers rush defense has struggled to contain some bruising running backs. Ahmad Bradshaw, Marshawn Lynch and Steven Jackson all put together performances that helped wear down the 49ers defense. Bradshaw rushed for 116 yards (4.3 ypc), Marshawn Lynch rushed for 103 yards (5.4 ypc) and Steven Jackson rushed for 101 yards (3.5 ypc). Even with Jackson's low YPC, it felt throughout like his bruising style helped set up Daryl Richardson's slashing style (58 yards, 8.3 ypc).

As the 49ers get ready for Monday Night Football against the Bears, the big question for Chicago is whether or not Jay Cutler will play. Jason Campbell is a capable if unspectacular replacement, but the real question whether Cutler plays or not is in the running game. The 49ers defense has been solid against the run against more athletic running backs, but the more physically-imposing running backs are a different story.

Pro Football Weekly took a look at key matchups this weekend and for 49ers-Bears they focused on the Bears rushing attack against the 49ers rush defense. Their main point was that maybe the Bears focus their rushing attack a bit more with Michael Bush than they have in recent weeks. Bush had ten carries against the Tennessee Titans in Week 9, but otherwise, over the last five games, he has had six or fewer carries in four games. Maybe that changes this week against the 49ers.

Forte is a good-sized running back, but he is generally more inclined to find the holes and use his moves to make things happen. Bush can maneuver well for a big man, but he has the size to make big things happen if he is trying to push the line. He has struggled with consistency in Chicago, but it is worth noting it was just last year that he put together some strong games in place of Darren McFadden during the second half of the Raiders season.

Is there concern the 49ers could get worn down by Bush, potentially setting up some bigger runs for Forte? If Jason Campbell ends up playing and is not prepared to go deep, I suppose that opens the door to bringing an extra guy down into the box. Either way I think we see a heavy dose of Michael Bush if the Bears are scouting the 49ers properly. It may not end up particularly successful, but I think they would be foolish not to open up that way.