CINCINNATI - The thought is one that all rookie quarterbacks force upon their fan bases. Usually, it occurs well before Week 13. You want the upside and excitement of a high-reward investment? This comes with it. More often than not, it comes well before now. The first hint of a downside, the crystallization of risk. On a gloomy day in a gloomy city, the Eagles confronted their own mortality. His name was Carson Wentz, and he was really, really bad.

Oftentimes, the numbers do an injustice to the performance. This was not one of those times. In a 32-14 loss to the Bengals that one can justifiably assume were the four worst quarters of his life, the rookie quarterback completed 36 of 60 passes for 301 yards, one touchdown, and three interceptions that should have been six.

Nor was it just one of those days. Not entirely, anyway. Wentz wasn't just bad, he was a special kind of bad, the kind that rekindles all of the concerns the Eagles inherited when they traded up to draft him. While much of Wentz's final line can be mitigated with a list of excuses that is as valid as it is long - the offensive line failed to block in either phase, his best receiver was a guy who entered the game with one week of NFL service and zero NFL catches, his defense gave him no margin for error - his biggest issue was a process kind of thing that transcended even the reality of his circumstances. It wasn't his inability to make the best of what the defense was giving him. Rather, it was his inability to recognize what, exactly, was there for the taking.

On at least three occasions, Wentz appeared to be completely unaware of the presence of a defender lurking in the vicinity of his intended target. All three balls should have been intercepted. None of them was. That's another thing about hanging on a young QB's every throw. There's a lot of irony involved. None of the three passes that the Bengals actually managed to intercept was as concerning as the three easy interceptions that they dropped. Simply put, Wentz looked a lot like the guy many expected they'd see as a rookie coming out of North Dakota State. That is, he looked confused. Confused by the presnap looks he was getting at the line of scrimmage, confused by the coverages he was seeing at the top of his drop, confused by the speed of the defense he was facing.

Case in point was one of his ugliest-looking balls of the game, a wildly overthrown duck of a third-down pass that missed a wide-open Dorial Green-Beckham for what would have been a big gain on the Eagles' fifth possession. Wentz locked onto Green-Beckham from the snap, presumably because he correctly read man coverage with no outside help. It was a slow-developing play, though, and if Green-Beckham hadn't shaken Dre Kirkpatrick with a slick-looking out route, he could have been out of luck, because at no point did he appear to survey the rest of the field for a Plan B.

The performance wasn't an anomaly. Wentz entered Sunday having thrown eight interceptions and 107 incompletions in his last 290 pass attempts after throwing no interceptions and 36 incompletions in 102 attempts during the Eagles' 3-0 start. His average yards per attempt had dropped by more than a yard. By no means was he awful. You just could just catch glimpses of flaws that weren't there in the first month. Flaws that on Sunday metastasized into the first loss of the season for which he bore a signifcant portion of the blame.

That Wentz had been building to this kind of stinker was largely obscured by the trajectory of the Eagles' season. The 3-0 start afforded him a tremendous amount of political capital. Losses to the Lions and Redskins offered more obvious culprits: a defense that couldn't stop the run, runners who couldn't hang onto the ball. Josh Huff's arrest and release dominated one week. Nelson Agholor's meltdowns dominated another. Mix in the magnitude of the victories they did register - the Falcons and the Vikings, both in first place at the time - and some questionable coaching decisions, and the public sphere found it both convenient and easy to avoid subjecting Wentz to the scrutiny that rookies of his ilk usually endure.

But the regression was there, even if it wasn't regression at all but another lesson in the illusory effects of small samples.

Ardent followers of the NFL might have suspected that something was amiss during that 3-0 start, that the transition from FCS to the NFC East couldn't be as seamless as it had seemed. Maybe the secondaries of the Browns and the Bears and the Steelers were as awful as advertised. Maybe their defensive coordinators had no way to know what kind of operation Doug Pederson and Frank Reich were running, and thus had no way to disguise their coverages. Pederson gave a subtle nod to the latter possibility after Sunday's loss when somebody asked him about the false-start penalties that continue to plague his offense.

"Some of it's a little bit on the quarterback, I would say," he said. "We're using so many snap counts and cadences to get indicators from the defense to kind of tip their hat a little bit and guys are geared up a little bit."

Later, Pederson mentioned the film that teams have accumulated on Wentz. The underlying theme was the same. The remarkable thing about the Eagles' 3-0 start was the ease with which their passing game seemed to operate. Rare was the moment when Wentz seemed caught off guard by the coverage he saw after the snap. In the NFL, if a quarterback can figure out the coverage he's facing before the snap, all that's left is to execute the throw. It's why Peyton Manning was so great, even when his arm was shot. The coverages don't look so easy to decipher anymore.

The bottom line: Wentz remains a project. The mechanics aren't as big of an issue with a better offensive line or a better receiving corps. To reach his potential, though, they'll have to be cleaned. That was always the reality, even if the Eagles made it easy to ignore. There's no such thing as a sure thing. Sunday simply served to hammer that home.