Mike Smith is out as defensive coordinator of the Buccaneers, replaced by linebackers coach Mark Duffner.

Riding a three-game losing streak and not showing any signs of being able to fix a porous unit that keeps undermining the team’s chances of winning, the Bucs dismissed Smith, a former Falcons coach, Monday after yielding 92 points in the first half of consecutive losses to Pittsburgh, Chicago and Atlanta.

Tampa Bay, which has the NFL’s second-ranked offense and No. 1 passing attack, rallied to make two of those games close, however pressure on coach Dirk Koetter to make a change had been mounting since Mitchell Trubisky threw a career-best six touchdown passes in the Bears’ 48-10 rout of the Bucs on Sept. 30.

The day after the loss to Chicago, Koetter said he had no intentions of dismissing Smith because the defensive woes were not the fault of any one person.

The Bucs had a bye after that game, but having an extra week to prepare for Atlanta didn’t turn out to be an advantage. The Falcons gained 219 yards and scored touchdowns on their first three possessions to open a 21-6 lead before holding on late for a 34-29 victory that apparently sealed Smith’s fate.

“I have the utmost respect for Mike Smith as a man and as a football coach,” Koetter said. “These decisions are always difficult, but our top priority here is to ensure that we do everything possible to help this team succeed.”

Through five games, the Bucs (2-3) are 31st in total defense at 439.8 yards per game. They’re last in pass defense (355.6), while also allowing a league-high 34.6 points per game.

Specter of Bell fades

Le’Veon Bell’s stall inside the Steelers locker room has been untouched for months. The Pittsburgh Penguins jersey. The black-and-yellow Jordans. Sweatpants. Cleats. His shoulder pads. Everything remains the same as it was when Bell walked out of the team’s facility in January to begin his standoff with the club.

The only thing that’s been disturbed is the chair. Some days a teammate’s workout clothes dangle from the back of it. On others — like Monday — a Steeler uses the seat as a spot to throw his lunch plate.

When Bell returns to reclaim his spot is uncertain. The first day of the team’s bye week came and went without the former Michigan State star coming in to sign his one-year franchise tender. What’s becoming increasingly clear, however, is that the Steelers are just fine moving on with Bell, or without him.

The anger over Bell’s decision to not report in time for the regular season opener has subsided. In its place is something akin to exasperation and resolve.

Pittsburgh (3-2-1) appears to be picking up steam. The last six weeks have been so eventful beyond Bell’s absence — from a sluggish start by the defense to wide receiver Antonio Brown’s weekly histrionics — the players aren’t even getting hit up for inside information on Bell’s plans when they get home from work.

Extra points

Vikings cornerback Mike Hughes has a torn anterior cruciate ligament in his left knee, ending a promising rookie season after six games.

... Coach Todd Bowles announced Monday that defensive coordinator Kacy Rodgers is returning to work this week after missing the past two games while dealing with an unspecified illness.

... Bills rookie Josh Allen is out indefinitely after hurting his throwing arm, leaving Buffalo in a quandary at quarterback.

... The Broncos have lost guard Ron Leary, their best offensive lineman, to a torn Achilles.

... Browns wide receiver Rod Streater suffered a neck fracture while covering a punt on Sunday and is out for the season.