Gary Landers/Associated Press

The Cincinnati Bengals are not a good football team, and Andy Dalton—who signed a six-year, $96 million contract extension in 2014—is not a good starting quarterback. It's that simple, and Dalton and his teammates provided us with plenty of evidence Sunday.

At home against a banged-up, beatable division rival, Dalton completed just 16 of 31 passes and committed five turnovers (four interceptions and a fumble) as the Baltimore Ravens hammered the Bengals 20-0. It was the second-lowest-rated game of the 29-year-old's career, and it marked the first time in over a decade that a team was shut out at home in its season opener.

Few expected that, but you shouldn't be surprised. The Bengals are coming off a six-win 2016 season and an inept 2017 offseason, and there are indications the team and its quarterback have regressed.

Despite the fact he was supposed to be building momentum entering his prime, Dalton's rate-based numbers plummeted in 2016. His passer rating dropped from 106.3 to 91.8, he ranked 24th among 30 qualified quarterbacks in touchdown rate and, as Pro Football Focus points out, he was particularly ineffective when facing pressure.

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That's why it was strange to see the team sit back and let two key offensive linemen—Pro Bowl left tackle Andrew Whitworth and high-ceiling right guard Kevin Zeitler—walk in free agency, even though they had the salary-cap space to re-sign both.

Without those two Sunday, the Bengals offensive line performed atrociously. Dalton took five sacks and was constantly under pressure. Whitworth's and Zeitler's replacements, third-year first-round pick Cedric Ogbuehi and fourth-year Texas product Trey Hopkins, struggled immensely. And Hopkins is already dealing with a knee injury.

Their peers—right tackle Jake Fisher, left guard Clint Boling and center Russell Bodine—weren't any better.

That doesn't absolve Dalton, and he knows it.

"I didn't give us a chance to win this game," the seventh-year signal-caller told reporters. "I didn't give us a chance to score the points we needed to win. It starts with me."

But the lack of support was a factor. It also didn't help that Dalton was without rookie first-round wide receiver John Ross, who is nursing a knee injury.

That's also on the team to an extent, because it knew Ross had health-related red flags prior to the draft. With rookie second-round running back Joe Mixon picking up just nine rushing yards on eight carries, the Bengals looked like a team closer to a rebuild than a return to the playoffs.

Of course, the Bengals and a lot of their fans probably remain in denial. But again, this isn't a mystery. Sunday's performance might have been a bit of an aberration—they'll win some games this season, or at least score some points—but the Bengals weren't able to experience much success back when the offensive line and defense were stronger.

Dalton had more support from those units when the Bengals made the playoffs in each of his first five seasons, but the Bengals lost all five of the playoff games they participated in during that run. In four playoff starts, Dalton has a completion percentage of 55.7, a touchdown-to-interception ratio of 1-to-6 and a passer rating of 57.8.

He's getting paid franchise-quarterback money, but he continues to show the football world he peaked early.

There were clues last year. Just look at his numbers from the second half of the season. After he posted a 98.0 rating and a 3-4-1 record during the first eight games of the year, Dalton's rating dropped to 85.4 during a 3-5 stretch to conclude a third-place season.

Andy Dalton's last 10 games Category Total Wins 3 Completion % 61.5 Touchdowns 10 Interceptions 10 Yards/attempt 6.6 Passer rating 78.6 Pro Football Reference / NFL.com

It didn't help that Dalton was without top receiver A.J. Green for a large portion of that period, but Green is healthy now. He was targeted 10 times, but only five of those throws were completed. Dalton was good on only one of the six passes he threw that traveled 15 or more yards.

Sunday's performance was extreme, but that doesn't mean it can be ignored. It's another indication the Bengals and their "franchise quarterback" are getting worse.

Brad Gagnon has covered the NFL for Bleacher Report since 2012.

Follow @Brad_Gagnon