As the Vikings prepare for Sunday's game with Chicago at Soldier Field, we asked Jeff Dickerson, who covers the Bears for ESPNChicago.com and ESPN-1000, to give us his up-close-and-personal scouting report. Here are four things you need to know … 1) The Bears are who we thought they were. Or are they? After a 51-20 destruction of Tennessee on Nov. 4, Chicago improved to 7-1 and was receiving plenty of seemingly justifiable praise as a Super Bowl front runner. The Bears defense was legit. Their special teams were delivering consistently. And the offense seemed serviceable at the very least. But now, Chicago has been humbled in consecutive losses to Houston and San Francisco. Which, of course, leads to inevitable skepticism about how good they really are. The Bears' record this season against teams that currently have winning records: 1-3. "Yes, they beat Indianapolis," Dickerson said. "But they played them in Week 1 with a rookie quarterback making his first start. So I don't really count that. The Colts were not the team then that they are now." And in games against top competition – at Green Bay in Week 2, vs. Houston in Week 10 and at San Francisco this past Monday – the Bears are winless, outscored 68-23. "It's justifiable to ask, are the Bears really a legitimate contender or did they get fat and happy on a very easy schedule?" Dickerson said. "We're going to find out there." Dickerson thinks the Bears defense is "a proven commodity" trying to carry the load for a questionable offense that has yet to prove it can consistently move the ball and score against quality defenses. 2) If a deep playoff run is going to happen, the Bears' defense will propel it. First, an attempt to explain that eye-popping takeaway figure – at 30 and counting through 10 games. "The Bears just expect it," Dickerson said. "And how do you really expect takeaways when so much of it is just luck and chance? But somehow they do it. And this year, I can't remember more than one or two times where they've missed an opportunity for an interception or a fumble recovery. Every chance that's come their way, they're capitalizing." Cornerback Tim Jennings leads the NFL with eight interceptions. Charles Tillman has forced a league-most seven fumbles. In all, 11 Bears have either had a pick, a forced fumble or a fumble recovery. Five defensive players have scored touchdowns, including Tillman and linebacker Lance Briggs, who have each scored twice. Tillman has received the most publicity this season and even had President Obama giving him a nod as Defensive Player of the Year a few weeks ago. Tillman is in his 10th season now, has 36 forced fumbles for his career and continues to be a force. "I appreciate his consistency," Dickerson said. "And I admire his toughness. The way he forces fumbles, he's going to change the way the game is played on defense. The punch is going to be a bigger part of the game going forward. So you can call Tillman a trend setter. … But he's always been this good. He'll get beat at times. Yet he's very resourceful, very consistent and so long as he can still run, he's going to keep playing." As far as any potential defensive flaws that were exposed by the 49ers in their 32-7 drubbing of Chicago on Monday, Dickerson believes covering tight ends can be an issue at times. San Francisco's Vernon Davis was targeted eight times and caught six passes for 83 yards, including an early 3-yard TD. 3) The Bears' offensive line has issues. Big ones. Just ask Jason Campbell, whose first start Monday subjected him to six sacks and 11 hits. San Francisco used a four-man rush for almost the entire night and the Bears couldn't handle it. Then, the 49ers notched their final score on a safety in which they only rushed three and still forced a Campbell fumble. "So five [guys] couldn't block three," Dickerson said. "It was pitiful." The Vikings don't need an exhaustive search to find evidence that Chicago left tackle J'Marcus Webb can be vulnerable. Remember last season's finale when Webb provided quarterback Josh McCown little protection from Jared Allen? Allen had 3.5 sacks and was in the backfield all day. There were also the struggles Webb had in Week 2 against Clay Matthews in Green Bay which led to quarterback Jay Cutler's haughty on-field meltdown and a wave of controversy that took over Chicago for several weeks. But even worse news for the Bears, Webb isn't the only tackle struggling. Wisconsin product Gabe Carimi, in his second season, has also been a turnstile at times on the right side. Chicago used a first-round pick on tackle Chris Williams in 2008 in hopes of solidifying their offensive front. And that experiment bombed. Now the selection of Carimi in Round 1 last year is looking perilous, too. "The guy was injured most of last year," Dickerson said. "And he's a very good run blocker normally. But his pass protection leaves a lot to be desired. So the fear now is whether he's a bust. I hesitate to throw that label on a guy this early. But the way he's playing, that's what people in Chicago are talking about. It's possible they go into the offseason desperately needing two new tackles and a new left guard." Go figure. The Bears have a trio of playmakers in Cutler, Matt Forte and Brandon Marshall that could be as solid as any QB-RB-WR trio in the league and yet they can't solidify the offensive line. 4) Marshall may be the Bears first Pro Bowl receiver since Marty Booker in 2002. The Bears traded for Marshall last March with a belief that his reunion with Cutler could be fruitful and relatively drama-free. So far, so good. Marshall has 69 catches (second best in the NFC) for 925 yards with eight touchdowns. His chemistry with Cutler is obvious. And he's a weapon defenses have to be aware of at all times. Yes, there's the occasional emotional flare-up. During Monday's beatdown in San Francisco, for example, Marshall admitted to becoming overheated with frustration on the sidelines. But the Bears are willing to live with those episodes so long as a) they're infrequent; and b) Marshall continues to be a force as an outside receiver. Marshall's three-TD effort against Tennessee was proof of his ability to make big plays. He also had three clutch catches for 28 yards on a game-winning drive in the final minutes against Carolina in Week 8. "He's a volatile guy and that's not going to change," Dickerson said. "When he doesn't get the ball, he's not that pleasant to be around. But on the whole, he's been terrific. He may not have great hands and will drop some passes. But he's a great receiver. He can go up and get the ball. He's a reliable playmaker. And I think the Bears are thrilled with how he's produced."