(CBS) After missing the last three games with a concussion that he suffered in Week 2 against the 49ers, Bears defensive tackle Jeremiah Ratliff was a full participant in Thursday’s practice, the best sign yet that he could be ready to return to the field. Chicago plays at Atlanta on Sunday afternoon.

Earlier this week, Ratliff was a limited participant in practice. The Chicago defense has held up OK in Ratliff’s absence with rookies Ego Ferguson and Will Sutton filling in respectably, but a return by an entrenched starter would be a boost for a team that’s struggled in falling to 2-3 and is failing to generate much of a pass rush.

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In other injury news, linebacker Lance Briggs (ribs), linebacker Shea McClellin (hand), linebacker Jon Bostic (back), safety Ahmad Dixon (hamstring), offensive tackle Jermon Bushrod (knee/ankle) and center Taylor Boggs (hamstring) missed practice.

Safety Chris Conte (concussion), cornerback Sherrick McManis (quad) and linebacker D.J. Williams (ribs) were limited participants. Center Roberto Garza (ankle) was a full participant.

Trestman not focused on getting 3rd/4th receivers involved

Through five games, 85 percent of the Bears’ targets and receptions have gone to four players — Martellus Bennett, Matt Forte, Alshon Jeffery and Brandon Marshall. Obviously, throughout the course of the game, an offense has a finite amount of plays and strives to get the ball in the hands of their best playmakers.

However, given the health issues at receiver and along the offensive line, the offense has had to make adjustments, ranging from the types of routes that are called to keeping in a tight end to help chip on the edge. In turn, single-coverage opportunities have arisen for third and fourth receivers, yet coach Marc Trestman said the team isn’t focused on getting them more involved.

“We’re really not,” Trestman said. “They’re part of the progression. That’s a pretty good group to be working to. I understand the question. We have things in the game  plan for them, but generally speaking, sometimes they’re a primary but most of the times they’re not because when you have a Matt and Marty and a Brandon and an Alshon and there’s only one football, you hate to waste those opportunities. Now we’re starting to build a little bit of that. We’re starting to get a little more comfort level to do that. But for the most part, the focus isn’t going to be on initially those other guys.”

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Finally at full health, offense is fed up with its performance

After finishing second in the league in scoring last season, the Bears maintained continuity to keep their strength a strength. All the coaches and players were retained, yet through five games, the Bears are scoring less and are having frequent miscommunications and miscues on the field.

Undoubtedly, injuries have played a part in that. When a receiver isn’t at full speed, it takes him longer to get into his route, which requires the offensive line to hold up a bit longer. When the offensive line is missing key starters, extra protection is needed from tight ends and backs, which limits eligible receivers.

Offensive coordinator Aaron Kromer said the team is finally at full strength and drew a line in the sand this week.

“Our offense this week really focused in and said, ‘We can’t have this. We are better than this, we need to score more touchdowns,'” Kromer said. “Not that we weren’t before, but it just was a collective group. It’s been such a fragmented group with the injuries to so many guys, that on Saturday we still weren’t sure who was playing on Sunday. So it was hard to come together, it was hard to have that bond.”

Turnovers and penalties have plagued the Bears as well. Over the past two games, they have more second-half turnovers than points and have had crucial presnap penalties, which must come to an end if this team wants to salvage the season.

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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.