Detroit, make some noise! The Detroit Lions are having their best season in almost forever. After steady improvement in the past two years, they finally broke into the upper echelon of the NFL. They had a 12-5 record after the regular season, and they knocked out the Los Angeles Rams and the Tampa Bay Buccaneers en route to the NFC Championship Game.

Now, only one hurdle remains between the Lions and a Super Bowl appearance in Las Vegas: the San Francisco 49ers. With this matchup set to kick off soon, it's worth looking at the key weakness that Detroit will need to shore up before the game.

The Lions' 2023 season

The Detroit Lions had one hell of a season in 2023. Entering the year, many expected them to be strong contenders in the NFC landscape.

They showed flashes of brilliance last season, and they came close to a playoff berth last year. An NFC North title was the lowest expectation for them.

Detroit did exactly that. The Lions were one of the best teams in the regular season in large part due to their high-powered offense. Jared Goff cemented himself as an elite quarterback, flanked by a bevy of weapons at every position. Their defense, while flawed (more on that later), were able to do just enough to not hold them back.

The real test, though, was in the playoffs. Can the Lions break the age-old curse upon them and win a playoff game? Yes, they did just that. In fact, they won two close games against the Rams and the NFC South champion Tampa Bay Buccaneers. They've been insanely good this year, and it seems almost nothing could stop them.

NFC Championship Game matchup

Unfortunately for the Lions, they will be facing the best team in the NFC (and arguably the best in the NFL). The San Francisco 49ers are the team to beat in the conference, and for good reason.

For most of the year, San Francisco looked near-unbeatable. A stacked offense and a suffocating defense gave them the No. 1 seed in the division.

The Lions do have some hope, though. After a week off, the 49ers looked off in their Divisional Round win over the Green Bay Packers.

They were expected to kick Green Bay's teeth in due to the talent difference. However, San Francisco allowed their rivals to hang on for an uncomfortably long time. It took a missed kick and a game-winning drive by Brock Purdy to put away the Packers.

Still, the 49ers are heavy favorites to win the NFC Championship Game against the Lions. A big reason for that is the Lions' biggest weakness, which is…

Coverage/Passing Defense

In some regards, the Lions and the 49ers are pretty similar. Both teams have a high-powered offense bolstered by an elite rushing attack and a creative passing game. Both teams, though, are lacking on defense.

The Lions' defense severely held them back in the past three years. There were flashes of Detroit's offense humming in 2021 and 2022, but an atrocious defense essentially negated all their hard work. This year, their defense has been a bit better in terms of yards and points allowed (19th and 23rd, up from 32nd and 28th last year).

Still, it's not been pretty watching the Lions play defense. They do have one of the best run-stopping defenses in the league, allowing the second-fewest rushing yards per game in the regular season at 88.4 and the second-fewest rushing touchdowns with eight.

The problem is the Lions' passing defense goes from below average to god-awful at the drop of a hat. They allowed the sixth-most passing yards per game at 274.4 per game.

What makes this mind-boggling is that they generate the highest pressure rate in the NFL per ProFootball-Reference. Aidan Hutchinson's rapid improvement allows Detroit to put immense pressure on the quarterback.

The problem, though, is that the Lions' secondary has been completely awful. They allow the most air yards by a country mile (3,100 in the regular season, next closest are the Buccaneers with 2,680).

Detroit isn't a big blitzing team either, so more often than not, the Lions have at least seven men in coverage, but they still get gashed. They also have the fifth-highest missed tackles, leading to a ton of yards after catch (2,133 yards, ninth-most).

Against the 49ers, this soft pass coverage will be exploited by one of the most fearsome offenses in the NFL. Even if 49ers star Deebo Samuel doesn't suit up due to injury, they will still have Brandon Aiyuk and George Kittle, as well as the versatile superstar Christian McCaffrey in the backfield. It's going to be a long, long night for Detroit's defense.