By Dan Durkin—

Editor’s note: This is the first piece in a series previewing the 2015 Bears as the first training camp practice approaches July 30. You can find them in one spot here as they’re posted.

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(CBS) Whether a defensive line has three hands on the ground or four, the goals remain the same: re-establish the line of scrimmage behind where the ball was snapped against the run and collapse the pocket against the pass.

Most games are won and lost in the trenches, and defenses are typically still built from the front (line) to the back (secondary). These principles certainly aren’t lost on Bears defensive coordinator Vic Fangio.

”The three down linemen to me are the heart and soul of the defense,” Fangio said during the team’s rookie minicamp in May. “If they’re getting pushed around, it doesn’t matter what you’re in, we’re in trouble.”

In 2015, the Bears will be a hybrid front that operates from a 3-4 base. That configuration is a 180-degree departure from what they’ve drafted for and executed on the field for decades. Undoubtedly, short-term growing pains loom from both a technique and personnel standpoint along the defensive line.

Let’s take a look at how the Bears stack up on the defensive line.

Likely starters:
RE: Ego Ferguson (23, second year)
NT: Jeremiah Ratliff (33, 11th year)
LE: Jarvis Jenkins (27, fifth year)

Other competitors: Cornelius Washington (25, third year), Will Sutton (23, second year), Brandon Dunn (22, first year), Eddie Goldman (21, rookie), Olsen Pierre (22, rookie) and Terry Williams (23, rookie)

Key contributor: Jeremiah Ratliff

Ratliff missed time last season due to a concussion and knee injury, but when healthy, he was exceedingly the Bears’ best defensive player.

Ratliff’s a complete player. He’s stout at the point of attack to anchor against the run and pass rushes with both brute power and lateral agility inside to puncture the pocket.

Not only is Ratliff a physically imposing player, he’s a student of the game. He works with linebackers to set the defensive fronts and orchestrates the defensive line games (stunts and slants) pre-snap. He’s a former All-Pro nose tackle in a 3-4 scheme, so his presence and experience will be an asset to his teammates and coaches in the meeting rooms.

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Ratliff’s versatility will allow him to be schemed both inside and out in base packages, as well as stay on the field in nickel situations to rush from two- and three-technique alignments.

Ratliff will be 34 at the start of the season but clearly has more gas left in the tank to be an impact player. He requires extra attention from blockers, which will create singles across the defensive line.

Potential breakout player: Ego Ferguson

As a rookie, Ferguson’s flash plays were limited, but the raw talents that made him a second-round pick — despite being only a one-year starter at LSU — were obvious. He plays with balance, power and fluid footwork, yet is unrefined with plenty of room to grow.

Ferguson was primarily deployed inside on the nose last season, but given his length and the current state of the roster, he will likely figure into the mix at defensive end as well. His re-dedication to conditioning and overall fitness in the offseason was evident, which will be a boon for him this fall.

Ferguson played in a 4-3 front at LSU but did man the nose at times when they played nickle 30-front sub packages. Thus, he’s learning on the job. But if he plays with consistent power at the point of attack when two-gapping and can stack blockers to keep linebackers clean, he will benefit a run defense that looks to be a problem area heading into the season.

Final thoughts: Only three players from this group have started a NFL game – Ratliff, Jenkins and Sutton. Accompanying that inexperience is a lack of blue-chip talent, making this group overall a weakness heading into the season.

In a best-case scenario, Ferguson takes the next step in his development and Goldman plays up to the potential that earned him a late first-round grade. The team invested high picks in both players, so the onus is now on them to play up to their athletic potential. Their emergence as dependable players would help Fangio develop a rotation with fresh legs late in games.

In a worst-case scenario, no player other than Ratliff becomes a difference-maker or requires extra attention from protection schemes. Consequently, Ratliff would be forced to play more snaps, which could wear him down late in games and late in the season, limiting his effectiveness. Teams would also be able to single up inside and slide their protection outside to where the pass rush threats exist in Fangio’s scheme.

This is a young, unsettled group, with mismatched pieces and skill sets. There are some developmental prospects on the roster, but as a whole, this group will likely struggle to stop the run and provide inconsistent pressure against the pass. Looking ahead, the defensive line projects to be a top priority heading into the 2016 season.

Position grade: C-minus.

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