By Jeff Joniak

By Jeff Joniak–

(CBS) The Bears (1-3) host the Vikings (2-2) at Soldier Field on Monday night. Here are my keys to the game.

Offense: Win on first down

The Bears haven’t been as successful running the ball on first down this season, averaging 3.7 yards per carry after registering a 5.3 yards-per-carry mark last year. Seventeen stuffs of Jordan Howard and Tarik Cohen have contributed to the decline, some of it coming on first down. They can’t play behind the chains against this Vikings defense, which clogs it up pretty good up front and has sure tacklers everywhere.

The Bears offensive line needs to get movement on Linval Joseph, who’s stout and quick up front. Chicago has to get bodies on linebacker Eric Kendricks in the running game as well. The Vikings are permitting 71.2 yards rushing per game, the third-best mark in the NFL.

So to balance it out, Bears rookie quarterback Mitchell Trubisky’s mobility needs to open some throwing lanes on first down. Opposing quarterbacks have completed 80 percent of their passes on the Vikings defense on first down, with a 121.1 passer rating.

Defense: Stop the big plays

The Vikings aren’t a dink-and-dunk offense. They make plays on the edges with the stunning starts of receivers Stefon Diggs and Adam Thielen. Preventing the big play is a point of emphasis this week from Bears coaches, who have noted the Vikings have made 38 “big plays” this season.

Diggs and Thielen have combined for 15 catches of 20 yards or more, and 30 of their combined receptions have gone for first downs. Whether Sam Bradford returns after missing three games with a knee injury or if it’s again Case Keenum at quarterback, the Vikings need to feel pressure from the Bears. The Vikings haven’t thrown an interception this season, and the Bears haven’t made an interception.

Special teams: Red alert on punt returns

Vikings punt returner Marcus Sherels is always a threat. He’s smooth in gathering the ball and has the toughness, quickness and speed to spoil the stew. For the Bears, lane integrity, sure tackling and the pinpoint targeting of punter Patrick O’Donnell need to collaborate to prevent Sherels from making a big play. He’s also outstanding as a gunner on punt returns and safety on kickoff returns. Bears rookie Tarik Cohen is also poised to break one, but it will require patience, given the hang time of Vikings punter Ryan Quigley, who leads the league at better than 4.7 seconds in that regard. Quigley has had only three of his punts returned this season, for a combined minus-1 yard.

Intangibles: Trubisky time

Trubisky’s start is as big as any headline in Week 5 there is in the NFL. The intrigue from fans and the general excitement of the No. 2 pick in the draft is palpable. It has been that way all week. Trubisky is calm and confident. A quick start should settle any nerves, and the confidence he has already instilled in his teammates would only grow as the success multiplies throughout a game. There will be highs and lows. How Trubisky and the Bears handle both will say a lot about the outcome. The excitement Trubisky brings into this game at Soldier Field needs to be used by the Bears to their advantage to keep the crowd engaged and loud.

By the numbers

The most important statistic for the Bears moving forward is turnover ratio. In the last three years, they’re a minus-31, including minus-7 this year, which represents the worst ratio in the NFL. If Chicago is going to win games and develop as a team, the ratio must flip.

Jeff Joniak is the play-by-play announcer for the Bears broadcasts on WBBM Newsradio 780 & 105.9 FM. Follow him on Twitter @JeffJoniak.

Watch & Listen LIVE