By Chris Emma–

Editor’s note: This is the seventh entry in a series of positional previews leading up to the start of Bears training camp. Find the rest of them here.

(CBS) Without a doubt, the most improved position for the Bears is linebacker.

In short time, general manager Ryan Pace brought the Bears from below replacement level — remmeber Shea McClellin, Christian Jones and many more? — to among the NFL’s best group. That’s what happens when you add Danny Trevathan and Jerrell Freeman to the mix a year after signing Pernell McPhee.

The Bears defense saw great struggles before Pace took the general manager’s office, struggles that were among the worst in franchise history. It began to change when defensive coordinator Vic Fangio took charge of the unit, but that was just the start.

While the Bears were able to find competence on defense, they were still missing the talent. Now, it’s here.

Linebacker will bring the Bears their defensive identity, led by Trevathan. Let’s look at the revamped unit.

Inside linebacker: Danny Trevathan, Jerrell Freeman, Nick Kwiatkoski, John Timu, Jonathan Anderson, Lamin Barrow, Jarrett Grace

The Bears’ greatest weakness from last season is suddenly their greatest strength.

Trevathan and Freeman will make the difference for this defense. Both will play nearly every down and have a track record of putting up big tackle numbers. With linemen Akiem Hicks and Eddie Goldman disrupting up front, there will be plenty of opportunities for the inside linebackers to secure the middle of the field.

Both Trevathan and Freeman left their previous teams due to unique contract situations, coming to the Bears on team-friendly deals. They each have that chip on their shoulders, looking to prove something.

Trevathan was a sixth-round pick out of Kentucky who earned his way with John Fox’s Broncos. As for Freeman, he came from the CFL to the Colts and became a standout at linebacker.

“We come from hungry backgrounds,” Trevathan said. “We’re out here to eat.”

Last season, Trevathan had 109 tackles in 15 games, which led the Broncos’ dominating defense. Freeman had 112 tackles in just 13 games. Freeman has 478 tackles in 57 career games, including a Colts single-season record 145 tackles in his rookie season of 2012.

The Bears’ two new inside linebackers will help transform their defense.

Outside linebacker: Pernell McPhee, Lamarr Houston, Willie Young, Leonard Floyd, Sam Acho, Christian Jones, Roy Robertson-Harris

Questions at edge rusher begin with the No. 9 pick of this past NFL Draft, the rookie Floyd.

Fangio came out and stated that Floyd’s slender frame isn’t a concern. Still, the Bears put Floyd on a nutrition plan aimed at adding size, which Floyd recently said had been working. The Bears would like to see Floyd emerge into the rotation at outside linebacker, but he’s going to have competition.

If healthy, McPhee will see the majority of snaps at one edge. Who gets the other spot?

Houston and Young came off knee injuries last season, adjusted to the new position and led the Bears in sacks. That impressed Fox and Fangio, who will certainly give the two ample reps in the rotation.

Floyd will have to not only prove he has the size to hold his own at outside linebacker but that he can simply manage a battle against an NFL offensive tackle. We may not know that until the reps get real in actual regular-season games. Floyd’s play as a rookie will be a subplot worth watching.

The Bears brought Acho back because they like his consistency at outside linebacker, plus he’s a key special teams player.

It’s likely that the Bears go six deep at outside linebacker, which puts the spotlight on Robertson-Harris, an undrafted free agent rookie whom the Bears prioritized. Jones was converted to the outside, which is likely better suited for him but a more difficult place to earn a roster spot. He may be cut in training camp.

Linebacker is certainly an improved position. Now, we wait to see how it all plays out.

Chris Emma covers the Bears, Chicago’s sports scene and more for CBSChicago.com. Follow him on Twitter @CEmma670 and like his Facebook page.