By Dan Durkin–

(CBS) With one game left prior to their bye week, the Bears (2-3) have an opportunity to get to .500 against the disappointing Detroit Lions (0-5) at Ford Field this Sunday.

It’s a must-win game for the Lions, whose season is on the brink. Sweeping changes could be in the offing if they drop to 0-6.

Here are a few storylines to focus on during Sunday’s action.

What to watch for when the Bears have the ball

Moving the pocket

The Lions lost defensive tackles Ndamukong Suh and Nick Fairley this offseason, but their defensive line remains a formidable group, particularly with their pass rush, led by defensive tackle Haloti Ngata and defensive end Ezekiel Ansah.

When Suh and Fairley were still on the team, their brute strength and ability to successfully rush with four allowed the Lions to drop seven into coverage to protect their secondary. However, under second-year defensive coordinator Teryl Austin, the Lions have played more man coverage and bring more second- and third-level pressure from the edges.

The Lions’ defensive front is active with its pursuit to the ball, and its overaggressiveness can be used against them. Judging by how well Bears quarterback Jay Cutler (hamstring) moved in the pocket last week against the Chiefs, he seems closer to full strength, which may allow offensive coordinator Adam Gase to get the bootleg play-action game going off the outside zone run scheme.

Perimeter runs

The Bears have utilized heavy personnel (three-tight end) groupings to run the ball this season. In doing so, they draw linebackers and safeties to the line of scrimmage and create extra gaps to be defended in the run game.

Matt Forte’s a patient runner who excels on stretch zone plays. While he has a designated aiming point, that scheme allows him to read the setup of his blockers and see where the crease in the defense is before making a decisive cut and pressing the hole.

The Lions defense has struggled this year with setting the edge and defending perimeter runs. They’re giving up 126 rushing yards per game, which ranks 27th in the league.

If the Bears are able to get movement at the line of scrimmage and cut off the backside contain, they can get positive yardage on early downs and set themselves up with third-and-short or manageable situations to control down and distance in what should be a close game.

What to watch for when the Lions have the ball

Line stunts from the Bears’ front

At the heart of the Lions’ offensive struggles is poor line play. They’re inexperienced in the middle and, collectively, they’re not an athletic group.

The youth in the middle has been especially problematic. Center Travis Swanson will be making his 11th NFL start and rookie left guard Laken Tomlinson his fourth. They haven’t been assignment sound on when to pass off a rusher or stay with them on interior stunts and line games.

Over the past three games, the Bears’ defensive front has been stout. While the pass rush wasn’t as consistent last week against the Chiefs as it was the previous two games, the defensive line is resetting the line of scrimmage and muddying the pocket.

Nose tackle Jeremiah Ratliff made his first appearance last week, playing 37 snaps. Rookie Eddie Goldman has improved each week and now gives the Bears a solid two-man rotation over the nose.

While the Lions play a lot of 11 personnel and may force the Bears into their nickel sub package on the majority of their snaps, look for defensive coordinator Vic Fangio to stunt and twist with his interior rushers. Outside linebacker Pernell McPhee will likely sugar (or “mug”) the A-gap in some of their hybrid fronts to create pre-snap confusion that may lead to post-snap disruptions in the Lions’ backfield.

Making plays on the ball

The Lions lead the league with 15 turnovers, and their nine interceptions also are a league-high mark. Embattled quarterback Matthew Stafford has thrown eight of those interceptions. Such numbers are common, as he’s finished in the top seven in interceptions in three of the last four seasons.

The Bears are one of two teams in the league (the Jaguars are the other) without an interception by their secondary. Given Stafford’s carelessness with the ball and his arrogant arm, that statistic may change after Sunday.

The Lions’ inability to run the ball is also a major factor. They rank dead last in yards per attempt (2.8) and yards per game (49). Their 87 attempts rank 31st in the league and have put the onus on Stafford’s right arm to move the football.

The majority of the interceptions Stafford has throw have been a result of questionable decision-making, but several have been the result of predictable play calls and him not being on the same page with his receivers about route adjustments based on the unfolding coverage.

Given the Lions’ difficulties running the ball, the Bears should feel confident defending the run with six- and seven-man boxes. Combine the Lions’ challenges with creating consistently sturdy pockets, and the Bears should have several opportunities to contest passes and potentially take a few away.

Dan Durkin covers the Bears for CBSChicago.com and is a frequent contributor to 670 The Score. Follow him on Twitter @djdurkin.