Head coach Dan Campbell announced the decision on Monday to part with Aubrey Pleasant in the wake of Sunday's 31-27 loss and a 1-6 start.
"I think Aubrey is a hell of a coach," Campbell said at his Monday news conference. "I've got a ton of respect for him. It was a tough decision, but we're in a production-based business, and after seven weeks I felt like this change needed to be made."
After two stagnant weeks produced six total points in losses to the New England Patriots and Dallas Cowboys, the Lions offense got back on track en route to a 14-0 lead against the Dolphins. But Detroit's defense couldn't hold the lead as Tua Tagovailoa torched the Lions secondary with 382 passing yards and three touchdowns on 10.6 yards per passing attempt.
This is nothing new in Detroit. Pleasant's dismissal arrives as the Lions field the NFL's statistically worst offense through the season's first eight weeks. The Lions rank last in average yards allowed (421.3) and points allowed (32.1) per game. They rank 27th out of 32 teams with 266.4 passing yards allowed per game. The Lions have scored 24 points or more in four of their six losses.
It's not clear how or if firing Pleasant will improve Detroit's defense. His dismissal won't improve a pass rush that ranked 29th in the league with 1.6 sacks per game. But Campbell clearly felt that something had to be done amid a five-game losing streak with his own job at stake in his second season in Detroit.
Pleasant was in his second season with the Lions after previous NFL coaching stints with the Los Angeles Rams and Washington Commanders. He got his NFL start in 2013 as a coaching intern with the Cleveland Browns. Safeties coach Brian Duker will take over Pleasant's former role.