Justin Rogers

The Detroit News

Allen Park — Detroit Lions coach Jim Caldwell likes to evaluate each season in quarters, and after the first four games, his team looked legit. The Lions came up inches short of sweeping the slate, and rebounded admirably from a gut-wrenching loss to the Atlanta Falcons following a controversial officiating decision.

The fast start, against what had been initially been viewed as a difficult stretch of opponents, put the Lions in position to earn a postseason berth in back-to-back seasons for the first time in 22 years. But three months later, on the cusp of a meaningless finale at home against division rival Green Bay, it’s easier to identify the underlying issues that were glossed over amidst the excitement of early-season success.

The troubles, as they often are in football, were largely tied to the trenches.

Lions general manager Bob Quinn invested so much into his offensive line this offseason, signing what he believed to be upgrades at right guard and right tackle. But injury issues hit early and often with the group.

Left tackle Taylor Decker suffered a shoulder injury requiring surgery in June, knocking him from the lineup the first eight games. Center Travis Swanson missed games with ankle and knee injuries, before ending his year on injured reserve with a second concussion in as many years. And the prized additions — T.J. Lang and Rick Wagner — also missed multiple games.

More: Lions vs. Packers preview: Go out on a high note

More: Detroit News predictions: Lions vs. Packers

On a unit where continuity is of the utmost importance, the Lions started 10 different combinations, and the results were predictable. If quarterback Matthew Stafford is sacked once against Green Bay, he’ll eclipse his career-high. And the running game continued to be among the NFL’s least effective, having gained fewer yards than anyone.

The defensive line wasn’t much better. The Lions banked on 2015 Pro Bowl defensive end Ziggy Ansah returning to form. In one of the team’s early season victories, he perpetuated the organization’s hope by delivering a vintage three-sack performance, against one of the league’s worst offensive tackles.

The mirage didn’t hold up long, and despite Ansah mustering 9.0 sacks prior to the finale, after another three-sack showing last week, his down-to-down impact never recovered to previous levels. The Lions tried everything they could to manufacture pressure, relying on a variety of blitzes, but will finish the year among the least successful teams doing so.

If you can’t run the football effectively, can’t protect your quarterback consistently, and can’t pressure the opposing quarterback regularly, it’s difficult to have sustained success. It’s especially difficult to do against quality opponents.

Detroit’s 3-1 start, which elevated expectations, didn’t hold up during an ensuing stretch against three playoff-caliber opponents, while another troubling trend became clear – the inability to start fast.

Against the Panthers, Saints and Steelers, the Lions fell behind double-digits twice and scored 12 or fewer points in the first half of each game. And while the team had crafted a reputation as the Comeback Cats a year before — setting an NFL record by completing eight fourth-quarter rallies — these Lions fell short each of these three games.

A run of cupcakes — a trip to Green Bay without star quarterback Aaron Rodgers, a visit from the winless Browns and a road trip against the Chicago Bears starting a rookie passer — provided three victories and temporarily renewed hope, only to be squashed by better competition. The Lions were handled in back-to-back games against the playoff-bound Vikings and Ravens, slapping them back to reality.

Going back to the year’s opening quarter, the Lions caught eerily similar breaks in wins over the Vikings and Cardinals when both teams’ starting running backs fumbled in the second half after suffering injuries. Those turnovers proved to be the turning point in the games. And the Giants, who turned out to be one of the NFL’s worst teams, were missing their best cornerback and star receiver Odell Beckham was clearly hampered by a lingering ankle injury.

The formula of beating bad teams and falling short against good ones still might have been enough to sneak the Lions into the playoffs, but a Christmas Eve loss to the lowly Bengals, who had lost their previous two games by a combined score of 67-14, was the final nail in the Lions’ coffin.

Detroit will finish above .500 if they beat the Rodgers-less Packers again.

But taking a wide-angled look at the season, it’s difficult to say they were ever good.

Packers at Lions

Kickoff: 1 p.m. Sunday, Ford Field, Detroit

TV/radio: Fox/760

Records: Lions 8-7, Packers 7-8

Line: Lions by 7

jdrogers@detroitnews.com

twitter.com/Justin_Rogers