By Jeff Joniak–

(CBS) The Rams (4-4) host the Bears (3-5) on Sunday at noon. Here are my keys to the game:

Offense: Defuse the bomb

An explosive, aggressive, and attacking Rams defense must be defused before it detonates.  A run-based attack might be the answer for the Bears.

Efficiency and production on first down running the ball would take some of the starch out of a lethal Rams pass rush.  Fourteen Rams have at least half a sack and eight have at least a pair of sacks.  It points to significant and impactful depth up front the Bears offensive line will need to battle. Two elite linemen need to be accounted for. Aaron Donald, the 3-technique defensive tackle, is explosive and a magician with his hands, while Robert Quinn bends the edge as well as any end in the game.  Donald and Quinn have combined for nine sacks.

In the secondary, solid corners Janoris Jenkins and Trumaine Johnson thrive in man coverage, while the safeties take away deep routes.  That cornerback duo has accounted for 18 pass breakups and only two touchdowns allowed. It’s a very fast unit, and one thriving at home. The Rams are on a streak of 10 quarters without permitting a touchdown and own the second-best scoring defense in the league at 13.8 points per game.

The scheme attacks in obvious passing situations, so staying ahead of the chains will be a critical component for the Bears.  Running to keep the pressure off could be the key to defuse the bomb that is the Rams defense.  Jay Cutler is excelling under pressure, and coordinator Adam Gase will devise some pass plays that pay dividends, but the windows of opportunity expect to be minimal.  When they present, the Bears must pounce. Check the status of receiver Alshon Jeffrey, who is questionable for Sunday’s game as he works through a sore groin.

Defense: Disciplined eyes and tackle

In four of the last six games, the Bears have allowed only one touchdown. It’s been six games since the Bears have given up a rushing touchdown.  Coordinator Vic Fangio impressively has mixed and matched combinations of players to meet the demands of the opponent despite personnel not entirely ideal fits for the 3-4 defense. The primary focus in St. Louis will be to curb the damage Todd Gurley is capable of inflicting.

Gurley, the rookie out of Georgia, is a powerful tackle breaker with top-end speed. He runs to and through the hole to daylight and then the trouble begins for a defense.  In accounting for Gurley, the defense must prepare for quarterback Nick Foles to work the play-action and a series of gadget plays that incorporate the dynamic receiver Tavon Austin.  Bears defenders need to break down and tackle these players and trust their eyes.  From screens to sweeps, Austin forces a defense to respect his speed, and the scheme’s misdirection package.

Forcing Foles to make quick decisions will be an important component for the Bears front seven.  Inside the twenty, Foles is completing only 47 percent of this throws with two interceptions. On third down, Foles is completing 46 percent of his passes with four interceptions, and in blitz situations, Foles is completing 54 percent of his throws with five sacks, but also five touchdowns. On the injury front, it was a week without practice for outside linebacker Pernell McPhee who has a sore knee, and another limited return for Shea McClellin. He’s missed three games with a knee injury, but is on the mend.

Special Teams: Tame Tavon

Bears punter Patrick O’Donnell will have to be careful with Tavon Austin.  A mishit based on the coverage plan could be a disaster. Austin owns one of the eight punt return touchdowns this season. He went 75 yards in the season opener against Seattle, but since has just 77 yards on 14 returns. That touchdown was the third of his career.

Austin’s speed makes him a threat with every possession. O’Donnell’s hang time is impressively third best in the league at 4.56 seconds, giving his gunners time to get to Austin.  Benny Cunningham is the primary kick returner, but the Rams have not parlayed that into great field position. They are 30th in the league in starts after kicks with nine inside their own 20. They average just 22.4 yards on kickoff returns and are 23rd in kick return yards.

Rams punter Johnny Hekker is one of only seven punters with a gross average of 48 yards or higher, and he is fourth in net average at 43.3, making him an effective weapon. St. Louis kicker Greg Zuerlein owns one of the most powerful legs in football. He cleared 61 yards outdoors in Minnesota last week, and has hit from 60 in St. Louis back in 2012 against Seattle.  However, Zuerlein has missed seven field goals this season, most in the league including two that were blocked.

Intangibles: Win third down

Winning third down keeps the Rams aggressive defense off Jay Cutler’s back.  St. Louis does whatever it can to force you into passing situations so they can tee off.  The Rams blitz on every down, and have six sacks on first down, five on second down, and five on third down. Those 16 blitz sacks are the most in the league. Offenses are only converting 25 percent of their third downs, needing 7-10 yards or more against the Rams. The Rams are one of only three defenses that have forced 70 negative plays.  Overall, they are fifth in third-down defense. The Bears are 30th.

Offensively, the Rams are as close to a balanced team as there is in the league in terms of play selection. They are second in rush percentage at 49 percent, and 31st in pass percentage at 51 percent. However, they rank last in the NFL in converting third downs at a clip of just 23.8 percent, so the addition this week of Wes Welker is purely designed to boost that rate. His decorated career includes stops in San Diego, Miami, New England, and Denver and he defines chain mover.

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