Potash's breakdown: Bears vs. Vikings

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WHEN THE BEARS HAVE THE BALL

ON THE GROUND

The Bears didn't do much in the run game against the Bills' 32nd-ranked rush defense last week: Matt Forte (14-49) and Chester Taylor (10-13) combined for 62 yards on 24 carries. But at least they tried. No telling what Mike Martz will do this week, but it won't hurt to try, even against the Vikings' No. 7-ranked run defense. The five teams that have beaten the Vikings have gotten 20 carries or more from their running backs, including the Saints, Dolphins, Packers and Patriots, all middle-of-the-pack or lower in rushing. And the Cowboys (31st in rushing) led the Vikings 14-7 at halftime, with running backs rushing 16 times for 44 yards, before collapsing.IN THE AIR

Jay Cutler was a game manager against the Bills -- his 188 yards and 6.3 yards per attempt were season lows for a full game -- and had his best passer rating (97.6) since Week 2 at Dallas (136.7). The Vikings offer better shots at big plays, but you need a run threat to take advantage of it. Devin Aromashodu, who has two catches in the last seven games, had seven receptions for 150 yards, including the winning 39-yard touchdown in overtime, against the Vikings last season. As always, pass protection is key for the Bears. The Vikings had six sacks last week against the Cardinals, who rank 31st in sacks allowed per play. The Bears are the only team worse.KEY MATCHUP: Bears LT Frank Omiyale vs. Vikings RE Jared Allen

Allen dominated Orlando Pace and Kevin Shaffer in the Vikings' 36-10 victory at the Metrodome last season, but he was silenced by Chris Williams and others when the Bears won 36-30 in overtime at Soldier Field. Omiyale likely will need some help to corral the big guy.WHEN THE VIKINGS HAVE THE BALL

ON THE GROUND

Adrian Peterson is second in the NFL with 957 rushing yards and is averaging 4.8 yards per carry with seven touchdowns. In six games against the Bears, he's averaging 122 yards and 5.3 yards per carry with 11 total touchdowns. But they're reeling him in -- from 7.6 yards per carry in '07 to 5.0 in '08 to 3.7 last season, when he had games of 25-85 and 24-94 and lost a fumble in each one. The Bears are third in the NFL against the run (84 ypg) and fourth in yards per attempt (3.5), but seven of their first eight opponents ranked in the bottom half of the NFL in rushing. The Vikings are ninth in yards per game (128) and seventh in yards per carry (4.6).IN THE AIR

At 41, in his 20th NFL season, Favre is better off throwing fewer passes than more. But he still can sling it against bad defenses: He was 36-for-47 for a career-high 446 yards last week against the Cardinals. The Bears are 19th in pass defense (226 yards per game) but eighth in pass yards per attempt (5.7) and probably would love to see Favre throw it 47 times today. The Bears are second in the NFL in opponent passer rating (68.9, five touchdowns, 11 interceptions). Then again, Favre threw 48 and 40 times against the Bears last season and had five touchdowns and no interceptions. The Vikings did not activate receiver Sidney Rice (hip).KEY MATCHUP: Bears LB Brian Urlacher vs. Vikings QB Brett Favre

Favre threw for 392 and 321 yards with five touchdowns and no interceptions against the Bears in 2009, but Urlacher missed both games with a wrist injury. In his last two games against Favre, Urlacher returned a pick 85 yards for a touchdown and had another that led to a key touchdown.X-FACTOR

The Vikings haven't been a team that has responded well to turmoil through the years, and they are knee-deep in it this week with Favre at odds with coach Brad Childress and anonymous players sniping at Childress for his criticism of Favre, among other things. In desperation mode at 3-5, the Vikings, especially with Favre at the helm, are talented enough to win in a rout but precarious enough to fall flat and make Childress' demise a fait accompli.SPECIAL TEAMS

The Bears made the most of a subpar special-teams game last week when Israel Idonije's blocked extra point and Brad Maynard's 46-yard punt to the 1-yard line played key roles against the Bills. If it becomes a field-position game, the Vikings might have an edge. They're No. 2 in the NFL in net punting (42.2); the Bears are 29th (34.7). Devin Hester, though, can change things in a flash.