CHICAGO — Dan Campbell keeps insisting he isn’t worried, and his team keeps playing clunkers of games.

Once the toast of the NFL, the Detroit Lions lost for the second time in three weeks on Sunday, 28-13, to the lowly Chicago Bears.

They turned the ball over three times, gift-wrapped 12 second-half points with careless defensive mistakes and managed just 61 yards of offense and no points in a hard-to-watch second half.

“I know that everybody’s trying to grab straws like what are we? What is this?” Campbell said. “I’m not worried. I know exactly what we are. We’re a team that’ll fight and we’ve got to do things right, cause any little mistake, man, it throws us off now. That’s just the type of team we are. But we got plenty here. We got plenty, and when we do things right, we’re pretty damn good. So we’ll get it cleaned up, man. We’ll move on.”

LIONS GRADE VS. BEARS: Both lines disappoint in rough showing across the board

Once considered a lock to win their first division title in 30 years, the Lions (9-4) now appear to be in a dogfight for the NFC North title with four games to play.

They lead the division by two games over the Minnesota Vikings (7-6) and face the Vikings twice in the next four weeks. The Green Bay Packers, who are 6-6 entering their Monday night game with the New York Giants, also are within striking distance of the division lead.

The Lions have four games left against teams with winning records. The Packers play one team with a winning record — the Vikings in Week 17. Minnesota also has a game next week against the Cincinnati Bengals, who have won two straight games with a backup quarterback.

“Obviously, this is the month of December, teams start trending up and stuff like that so if we want to go to where we want to be, we got to make sure we’re playing our best football every game, getting better every game,” outside linebacker Julian Okwara said. “We can’t be sitting here making mistakes that bite us. We’ll get it right, though. We just got to clean it up.”

JEFF SEIDEL: Lions do the impossible: Take a step back while falling flat on their face

The Lions have lots to clean up after one of their sloppiest games of the season Sunday. They committed eight penalties, including a handful that stalled drives. They failed to pick up a first down on their first five drives of the second half.

And with the game tied at 13 late in the third quarter, they fell victim to a series of self-inflicted boneheaded mistakes.

The Bears (5-8) scored the go-ahead touchdown with 1:36 to play in the third quarter on a 38-yard touchdown pass from Justin Fields to DJ Moore. The Bears lined up in an offensive formation on fourth-and-13 hoping to draw the Lions offsides, and when Aidan Hutchinson jumped across the line of scrimmage, Fields threw deep to Moore, who ran by cornerback Jerry Jacobs.

The touchdown came one play after officials did not throw a flag for intentional grounding after Okwara hit Fields near midfield as Fields threw incomplete off one of his offensive lineman’s legs.

“The coaching point is discipline,” said Campbell, who declined comment on the non-penalty call. “It’s discipline. Across the board. And that’s why I bring that up. We’ve been a disciplined team and we just weren’t enough today and they were.”

Jared Goff and Graham Glasgow fumbled a quarterback-center exchange at the Lions’ 29-yard line on the next series, and the Bears scored five plays later when Fields scrambled around right end on third-and-goal from the 11.

Hutchinson ran a stunt with Levi Onwuzurike on the play, but Onwuzurike, playing his first game since Thanksgiving in place of the injured Alim McNeill, couldn’t get to the edge, giving Fields a clear path to the end zone.

SHAWN WINDSOR: Lions beat themselves in worst outing of season, extending troubling trends

“I really just saw green grass,” Fields said. “I'm looking for DJ to throw because he was one-on-one in kind of the back corner, but then I looked down and saw green grass right there, so just ran.”

The Lions failed to convert a fourth-and-1 run on their next possession, giving the Bears another short field for a field goal. And in cold and blustery conditions, the Lions couldn’t muster enough from their passing game to threaten another comeback in the final 9:20.

The Lions beat the Bears in November when they rallied from 12 down with 3 minutes to play. They committed four turnovers in that game and three the next week in a Thanksgiving loss to the Packers.

They’ve also squeaked by the Los Angeles Chargers in a shootout and held off a New Orleans Saints rally to win a nipper in their five games since the bye.

“If we want to be a playoff team, we got to play like a playoff team,” Lions safety Kerby Joseph said. “I feel like, like I said, when you’re at the top everybody want to bring you down, everybody gunning for you. Before we had these boys at our home and we did what we were supposed to do, and come in this time they was ready for us. I feel like if you want to go to the top, we got to play like we’re ready to go to the top.”

Fields completed 19 of 33 passes for 223 yards for the Bears and added 58 yards rushing on 12 carries, his first game with less than 100 yards rushing against the Lions since 2021. Moore had 88 yards from scrimmage and also scored on a 16-yard run.

Goff was 20 of 35 passing for 161 yards for the Lions. He threw an 8-yard touchdown pass to Josh Reynolds in the second quarter and two interceptions, both on nothing-to-lose fourth-and-long plays.

He threw three interceptions against the Bears in November and has 10 interceptions on the season, but said he has "a ton of confidence that we're going to clean" things up.

"A little adversity isn't the worst thing in the world at this point in the year," he said. "This is sure it.”

Contact Dave Birkett at dbirkett@freepress.com. Follow him on Twitter @davebirkett.

This article originally appeared on Detroit Free Press: Sloppy Detroit Lions lose again: 'Adversity isn't the worst thing'