LAKE FOREST, Ill. — When Jared Allen walked back out onto the practice field at Halas Hall Wednesday after losing 15 pounds due to pneumonia, it signaled a reboot to a season that hasn’t really begun for him.

The same is true for any number of Chicago Bears who have been missing games and practices, but suddenly are back into the possible mix for Sunday’s game at Carolina. The end result, they hope, is an end to the inconsistency that has been a problem on both sides of the ball.

Defensively, besides Allen, tackle Jeremiah Ratliff seems on the verge of a return from a concussion suffered early in the second game. Offensively, for the first time since Week 1 starting center Roberto Garza and guard Matt Slauson practiced. And just as important to quarterback Jay Cutler, wide receivers Brandon Marshall and Alshon Jeffery also got on the field.

Marshall’s absence in practice had started to lead to questions about whether he had an ankle injury more serious than the Bears let on, or whether he should actually sit out a game or two. Marshall has just three catches combined the past two games, and was targeted only 12 total times.

While most of those practicing were initially limited, Marshall was 100 percent involvement. His ability to go vertical and to get downfield on the deep ball had obviously been limited through the last few weeks.

“Brandon got through practice, did everything,” coach Marc Trestman said. “That’s a good sign. Professional football players need to practice. And some need to go limited at times because they just need to do that. And we do some of that. But it was good to have him back at full speed today.”

It’s hoped the end result of getting players back on offense to face Carolina is more consistency. The offense — like the defense — has been the height of inconsistency throughout the first quarter of the season. Trestman doesn’t want to blame the injuries for this, but it’s a valid point when various players are in and out of games and practices.

“No. 1 we haven’t scored the points that we’d like to score — that’s No. 1,” he said. “We take a lot of pride in that and we haven’t scored the points over the first four games.

“If we look at it game by game we’re playing in different environments against different kinds of teams. I think the most important thing is we want to take care of the football and give ourselves a chance each and every week to be in the game in the fourth quarter. This (past) week we didn’t. We didn’t give ourselves a chance. I think we showed this week that we’ve got the ability to run the ball. I think we’ve shown we’ve got the ability to throw the ball. We just haven’t done it consistently in my opinion, and consistently finish drives to where we want.”

The Bears rank 20th on offense, broken down to 20th rushing and 14th passing.

Trestman doesn’t want to blame the injuries, but a drop from second in the league to 20th has to be the result of something.

“We’ve shown signs, both running and throwing the ball, of being able to do it very effectively,” he said. “We haven’t finished enough drives to be able to score enough points to win games that we haven’t been able to win.”

Their defense has been much like the offense. They failed to stop the run in Week 1, then played well for two weeks and failed to show up in the pass rush or secondary against Aaron Rodgers and Green Bay last week.

Having Allen to face Cam Newton and the Panthers would be a huge boost, but then again the Bears can’t really say they’ve had Allen all year. And it goes back to training camp. He missed time due to a shoulder injury and the birth of a child, got off to a slow start as a pass rusher because they asked him to take more of a run-stuffing mode against Buffalo, San Francisco and the Jets, the got sick early last week.

Between coughs Wednesday, he said he dropped to 239 pounds but has added weight since he had been sick and is hopeful of getting back on the field Sunday. Whether a defensive end can play at that reduced weight remains to be seen, especially against a Carolina Panthers team that can test the edge with the running game and with quarterback Cam Newton getting outside to throw.

“I’m still a little light,” Allen said. “But I haven’t gotten in that rhythm or that groove of what I’m used to playing in. It’s not anybody’s fault.

“Preseason was preseason. I didn’t do much in preseason in Minnesota, either. But it’s more familiar territory so-to-speak. Having a new baby, there’s been a lot of change in my life. But it’s a good thing. I was playing good ball. I was sad I missed this game because coming out of the San Fran game and then the New York game I felt like I was really starting to get into the rhythm of this defense of where we were at stopping the run and then even though I didn’t get Geno (Smith) on the ground, I had some really good rushes in the fourth quarter and I really felt like my game was where it needed to be going into that week. And I still feel that.”

Linebacker Lance Briggs thinks getting both defensive linemen back can make for a totally different look. The Bears were using rookies Ego Ferguson and Will Sutton at tackle while asking LaMarr Houston and Willie Young to take more snaps at end.

“It’s big, it’s huge,” Briggs said. “Having (Allen), Ratliff last weekend would’ve been big — especially in getting to the quarterback.

“If Jared plays, that’s going to be a big boost.”

The defense looks to get one extra boost in the secondary. Reserve cornerback Sherrick McManis practiced on a limited basis after a Week 2 quad injury. He would be on the field in the nickel while Isaiah Frey could be put back on the bench. Frey, who was not on the team after preseason ended, was brought back after McManis’ injury and the season-ending injury to Charles Tillman. Frey was burned repeatedly by Packers receivers last week.

If McManis returns, the Bears could go with their original plan of using Tim Jennings in the nickel back position while putting McManis at right corner on passing downs. McManis came to the team as a special teams player, but this preseason showed enough in coverage that they chose to cut veteran Kelvin Hayden and keep McManis to be a backup nickel.

All the defensive injuries at least gave the Bears a chance to assess their youth.

“Every play that those guys play is a tremendous experience for them in practice or in the game,” defensive coordinator Mel Tucker said. “So we all learn from it as coaches and players. We use those teachable moments to move onto the next game. That’s what we’re doing right now.”

They’d like to have the chance to let the younger players digest what they’ve learned a little longer this week and in the future.

SERIES HISTORY: Eighth regular-season meeting. Bears lead series 5-2 and have won three straight. Carolina’s last win came in Charlotte in 2008 (20-17).

–LB Lance Briggs did not practice Wednesday due to what the team called a knee injury, but Briggs made light of the situation as if to suggest it was more a veteran’s day off to rest than an actual injury.

–LB D.J. Williams missed Wednesday’s practice with what was termed a neck injury.

–S Ahmad Dixon missed Wednesday’s practice due to a hamstring injury suffered in Sunday’s game on kick coverage duty.

–LB Shea McClellin continues to miss practices due to the broken hand which has kept him out of the last two games. Jonathan Bostic continues to take snaps in his place.

–S Chris Conte went through a full practice Wednesday after he had been limited through most of last week due to a shoulder injury. He played all of Sunday’s loss to Green Bay without a problem.

–LT Jermon Bushrod was out of Wednesday’s practice due to a knee injury.

GAME PLAN: Defensively, the closest the Bears have come to facing a quarterback like Cam Newton was Colin Kaepernik, and they held him in check. But Kaepernik was more likely to run than Newton, who always is looking down the field to inflict damage.

The secondary has to be prepared to play a great deal of zone, but their biggest problem will be shadowing tight end Greg Olsen in the seam routes as well as in the flat. They may be able to devote more attention to covering him than in the past because the Panthers no longer have Steve Smith as their wide receiver threat. Smith was always a Bear killer.

The pass rush can’t be free-wheeling and will have to be restrained because of Newton’s mobility – albeit a bit limited due to injuries this season. He has a tendency to run for the first down sticks and slide, or run out of bounds at them, but not try to get as many yards as he can. Making Newton stay in the pocket and beat you is the best approach, but he’s certainly capable of doing this. Because of Olsen’s abilities, the Bears may need to be in nickel defense most of the day. Olsen is like having another wide receiver.

On offense, the look the Bears get will be awfully familiar. The Panthers under Ron Rivera play a very similar defensive scheme to theirs, using mixed zones and trying to get home with four rushers.

Jay Cutler will need to attack under the coverage with passes to tight ends Martellus Bennett and Dante Rosario and running back Matt Forte. Delay runs, like they used last week, can be effective with linebackers making deeper drops. Brandon Marshall and Alshon Jeffery like to use their height on slants and post patterns, and they should get the chance against the cover-2 or other zones.

It won’t be a case of going deep, unless they try throwing along the sidelines for jump-ball situations before the safety can come over to help pick up coverage.

MATCHUPS TO WATCH:

Bears DE Jared Allen, who did not play last week and is without a sack, vs. Panthers left tackle Byron Bell, who is 6-5, 340. Because of Allen’s illness last week, he’s about 100 pounds lighter than Bell and his strength is in question. He already was struggling this year against massive tackles in two of the games he played, and in another was handled by a simple 300-pounder. The Panthers running game has been nonexistent, as they rank 29th in yards per game. But even with a handful of injuries to their backs, look for Carolina to come out running and go at the left side to take advantage of where the Bears are light and possibly not full speed.

Bears CB Kyle Fuller, who took a step back last week after three interceptions the first three games, vs. Panthers wide receiver Kelvin Benjamin, who is 6-5, 240. Fuller is about 5-10. The Bears will get to see how opposing defenses feel when they go against Brandon Marshall and Alshon Jeffery. There should be plenty of attempts by Carolina to take advantage of that height advantage, especially in the red zone. Benjamin has three TD catches and 21 receptions overall for 329 yards.

Bears TE Martellus Bennett, who is off to his best start ever with a team-high 29 catches, vs. Panthers middle linebacker Luke Kuechly, who has two passes defended and a forced fumble. The Panthers use Kuechly as a sort of Brian Urlacher Light. He’s an inch or two shorter and 15 pounds lighter, and not quite as fast. But he is a good pass defender and makes a quick drop in the zone. They’ll have him back guarding the middle where Bennett has done a lot of his damage. In shorter routes, it could be a strong safety or another linebacker on Bennett, but when he goes for the seam or is a third down target, it’s usually going to be Kuechly that has him.