After CB Kyle Fuller struggled Sunday, how bad can Lions burn Bears?

Kyle Fuller was the one with his back turned to the quarterback when the man he was covering, Davante Adams, caught the Packers’ 19-yard touchdown Sunday.

It wasn’t all his fault. He thought Eddie Jackson was behind him, but the Bears safety was late to help because he flowed to the opposite side of the field.

“I should have been there,” the rookie said Wednesday. “It was my fault. … That was on me.”

Rushing over the right tackle, Leonard Floyd spun inside — and Brett Hundley scrambled right, with no pressure, before making the throw. Floyd decided to freelance too late; had done so earlier, he could have still had an angle on him.

“If they do go inside,” defensive coordinator Vic Fangio said, “they’ve got to make it.”

Floyd didn’t, and Fuller paid the price. Not that he needed any help struggling Sunday. The Packers were 8-for-10 for 127 yards when targeting Fuller; one of his two pass breakups was a dropped interception.

Fuller was surprisingly solid to start the season — nonetheless, teams weren’t afraid to target him — but posted his worst game Sunday. Defensive coordinator Vic Fangio said “he’s been fine” this week, trying to fix his mistakes. The Bears could seek reinforcements from Marcus Cooper on Sunday; if not, Fuller better have a short memory.

“I hope so,” Fangio said. “You need to, at that position, in this league.”

The Lions will stress the Bears’ pass defense — which has allowed the 10^th fewest passing yards this season — in a way Hundley never could. Matthew Stafford’s offense ranks sixth in the NFL with 27.1 points and eighth with 254 passing yards per game.

“When you become a great quarterback, it’s because there is no one way to play you,” Fangio said. “He’s good against pressure. He’s good against three-man rush. He’s good against different types of coverages. So you just have to mix it up with him.

“Obviously, a good pass rush always goes a long way in helping play against any quarterback. But you’ve got to be able to mix up what you’re doing against him because he’s good enough now.”

He can extend plays, too — just like Hundley did on the touchdown.

“In the secondary, we have to cover longer,” Jackson said. “Things like that — what happened last week, we can’t let that happen.

“When the quarterback scrambles, we gotta stick with our guy and just really keep him contained and just keep peppering him and get him uncomfortable in the pocket.”

Golden Tate, known for his yards after catch, leads the Lions in receiving yards. The Bears will need physical tackling, from Fuller or elsewhere.

“Anything but your best effort in tackling, both from a mindset and technique standpoint, is going to be needed,” Fangio said.