DETROIT (AP) — In each of the first two years of Dan Campbell’s tenure with the Detroit Lions, he’s had to make major changes in his coaching staff midway through the season.

Last year, he took play-calling duties away from offensive coordinator Anthony Lynn after an 0-8 start and let him leave after the season.

On Monday, he fired defensive backs coach Aubrey Pleasant with the team at 1-6.

“It was a tough decision, but we’re a results-based business,” Campbell said Monday. “After seven weeks, it just felt like a change needed to be made.”

After allowing an average of 290 passing yards per game in a 1-3 start, the Lions had shown some signs of improvement in holding New England and Dallas under 200 yards. But that was New England with rookie Bailey Zappe and Dallas with Dak Prescott coming back from an injury.

The secondary struggled again in Sunday’s 31-27 loss to Miami — a game the Lions led 14-0 and 21-7.

Tua Tagovailoa went 29 for 36 for 382 yards and three touchdowns without an interception, with Tyreek Hill (12 catches for 188 yards) and Jaylen Waddle (eight catches for 106 yards) combining for 20 catches, 294 yards and two touchdowns.

Safeties coach Brian Duker will take over for Pleasant.

“I think Aubrey is a hell of a coach — I’ve got a ton of respect for him,” Campbell said.

“But we need to get everyone on the same page and cut our mental (mistakes) in half.”

Entering Monday, the Lions defense is ranked last in the NFL in points and yards allowed and the pass defense has allowed an average of 266.4 yards per game and 12 touchdowns with only two interceptions.

WHAT’S WORKING

After scoring six points combined in losses to the Patriots and Cowboys, the Lions showed what their offense can do with Amon-Ra St. Brown and D’Andre Swift on the field. Detroit put up 393 yards and scored 27 first-half points.

There were still some hiccups — they didn’t score in the second half, allowing Miami to rally for the win — but that was the offense that was among the league leaders for the first four weeks.

WHAT NEEDS HELP

The defensive backs are getting some assistance with the coaching move, but it might not be enough.

The defense couldn’t stop Tagovailoa, Hill and Waddle. They caught 20 passes on 23 targets for an average of 14.7 yards per catch.

That was a key reason the Dolphins were 9 for 13 on third and fourth down and kept the ball for 34:22 to Detroit’s 25:38.

“We didn’t hit them at the line, and that was part of the game plan,” Campbell said of Waddle and Hill. “We didn’t disrupt them, and when you let them get into your defense, it turns into a track meet. We didn’t want that.”

STOCK UP

Cornerback Jerry Jacobs (knee) played nine special teams snaps in his second game back from a torn ACL. If he’s ready to play a bigger role on Sunday against the Green Bay Packers, he could give the defense a boost.

“We want to make sure Jerry is ready to go —we’re trying to get his confidence back and get his feet back under him,” Campbell said. “Once we feel like he can take the load, he’s going to get his chance.”

STOCK DOWN

CB Amani Oruwariye has gone from the leader of the 2021 defense to someone who is only on the field because of injuries. After his promising season last year, the Lions were looking forward to having two shutdown corners in Oruwariye and Jeff Okudah, but it hasn’t happened.

INJURIES

The Lions got St. Brown, Swift and Jacobs on the field, even if they weren’t 100% and didn’t sustain any new losses.

KEY NUMBER

Four — the number of wins Campbell has in 24 games as Lions coach. Everyone knew he was coming into a tough situation, but it is difficult to see much progress in 4-19-1.

NEXT STEPS

Campbell, defensive coordinator Aaron Glenn and Duker are going to have to come up with a plan to stop Aaron Rodgers and the Packers on Sunday.