By Dan Durkin—

Editor’s note: This is the second 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.

(CBS) In a pass-first NFC North that features Aaron Rodgers, Matthew Stafford and Teddy Bridgewater, harassing the quarterback will be paramount to any success the Bears defense plans on having this fall.

One of the primary schematic advantages to running a 30-front — as the Bears will in 2015 — is offenses must account for all four of the linebackers potentially being a part of the rush package. In Vic Fangio’s scheme, the primary pass rushers are the outside linebackers.

General manager Ryan Pace inherited a roster built for a 40-front, so the challenge became discerning which players already on the roster transcended scheme and where the team needed to supplement in free agency. However, Pace is keenly aware of what the most important trait at the position is.

“Pass rush is the first thing that comes to mind,” Pace said at the NFL Scouting Combine. “Edge speed. The ability to hit the quarterback. And then the ability to set the edge and get off a block.

“But pass rush is the No. 1 priority.”

The Bears’ collection of outside linebackers features players who’ve been successful at hunting down quarterbacks, mainly as hand-on-the-ground defensive ends. There’s enough available talent to pressure the quarterback, but how consistently? Furthermore, who among that group can be trusted to reliably drop into coverage when not a part of the rush?

Those are some the biggest questions facing the Bears’ group of outside linebackers heading into the season.

Likely starters:
ROLB: Pernell McPhee (26, fifth year)
LOLB: Lamarr Houston (28, sixth year)

Other competitors: Jared Allen (33, 12th year), Willie Young (29, sixth year), Sam Acho (26, fifth year), David Bass (24, third year) and Kyle Woestmann (23, rookie)

Key contributor: Pernell McPhee

McPhee flourished in a part-time role in Baltimore, playing in a rotation behind elite pass rushers like Elvis Dumervil and Terrell Suggs. He finished with 7.5 sacks on just more than 500 defensive snaps in 2014. Will McPhee’s productivity increase with more snaps? Clearly, he’s a better player attacking downhill, but is he ready to play as a dropper? Time will tell.

Undoubtedly, McPhee possesses all the necessary traits to succeed. He has violent club and swat moves and rushes with proper length, leverage and relentlessness off the edge. He’s scheme versatile and was productive both inside and outside in Baltimore. However, he was most effective when rushing from his feet, where he can set blockers up with footwork, then convert that speed to power to dictate the engagement.

McPhee’s been brought up in the NFL under a complex, attacking hybrid defense, which is a boon for Fangio’s new installation in Chicago. Look for McPhee to start out on the right side as the team’s primary pass rusher and potentially kick inside to two- and three-techniques in nickel sub packages as Fangio gets creative with situational pass rushers like Allen and Young.

Potential breakout player: David Bass

Despite playing limited snaps over the past two seasons, Bass has a knack for making impact plays at crucial moments in games. If the new staff has truly wiped the slate clean with their evaluations and isn’t giving away snaps, he has a chance to earn playing time.

While Bass has never played in a 30-front, it may be the be best scheme for his physical traits, as he was more of a tweener defensive end in a 40-front. He’s athletic enough to play in space and open his hips to spot drop in pass coverage. He’s also explosive and long enough to win a single (one-on-one block) and bend the edge from the outside. He plays with excellent vision and instincts when stalled in his rush, getting his hands up to disrupt throwing lanes.

How many reps Bass gets remains to be seen, but if allowed an opportunity, he has the potential to earn a spot in the rotation on the left side.

Final thoughts: There’s clearly talent in this group, but how it all comes together remains to be seen.

Complicating matters is that two of the veteran competitors — Houston (knee) and Young (Achilles) — are recovering from serious leg injuries. Given the severity of his injury and the fact it happened in Week 16, Young’s availability at the beginning of the season is a question mark. Houston, on the other hand, will be nine months removed from his self-inflicted ACL tear when camp starts.

From a fundamental and assignment perspective, the biggest challenge for the entire group will be dropping into coverage.

Looking back at Fangio’s first year in San Francisco, he deployed rookie Aldon Smith almost exclusively from the right side as a rusher with no coverage responsibilities. He may be tempted to do the same with McPhee this fall. Houston, Acho and Bass should battle for the spot opposite McPhee.

The missing element for this team is a true speed rusher. McPhee’s more of a power and leverage rusher. However, if Houston is healthy and Allen adjusts to playing from a two-point stance and embraces playing a situational role, Fangio should be able to scheme pressure on a weekly basis.

Position grade: B.

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