No knock on the Washington Redskins, Carolina Panthers, Dallas Cowboys, or Tampa Bay Buccaneers - OK, maybe a little knock on the Bucs - but the Nick Foles Development Thermometer will get a true high-temperature test Thursday against a big-boy NFL defense.

It should be interesting, and if Foles can perform competently and confidently against the Cincinnati Bengals, then the organization will know even more than it did after the rookie's four previous starts against lesser units.

The Bengals are ranked among the top dozen defenses in the league against both the pass and the run, and overall they are the sixth-ranked defense in the NFL. In real, not numerical terms, Foles will also have to deal with a defense that is the best around at bringing pressure on the quarterback. Cincinnati leads the NFL in sacks and has enough veteran tricks to make it a long game for an inexperienced quarterback.

"I'm going to have to do a great job with blitz pickup," Foles said Tuesday. "We're going to have to see what they're doing to us, and the big thing is to just run our offense well."

Yes, that would be a fine idea, although the Bengals are good at finding ways to disrupt that game plan for their opponents. This will be Foles' biggest challenge to date. He won't be a washout if he fails it, but if he passes, this really could be something special taking place.

Along with providing a test of Foles, the Thursday night game will give a glimpse of the guy whose name will be mentioned as a replacement if the Eagles decide to fire Andy Reid after this season.

Cincinnati coordinator Mike Zimmer has built successful defenses with both the Cowboys and Bengals, and he has been interviewed for four head coaching jobs in the last two years. One of these days, someone is going to give him a job, and if the Eagles are intent on wiping out any vestige of the Reid regime, it could be that a defensive coach in the top spot would help that process.

With the Bengals, Zimmer has fashioned the scheme, along with head coach Marvin Lewis, without the presence of very many high draft picks or the kind of talent that immediately jumps off the page. He would have a similar task in Philadelphia, where the front office's low-round "finds" haven't performed well over time and where the rest of the unit is made up mostly of busted picks or mercenaries.

Cincinnati is built around a very strong line, and one that is most dangerous in the middle, where tackle Geno Atkins has 101/2 sacks. It's more difficult to block the middle of the line (obviously, the tight end can't help as he does against defensive ends), and the Bengals, as a result, can get very good pressure with just four rushers and still keep seven men in coverage.

"It's not a defense you face every week," Eagles backup quarterback Trent Edwards said. "It's one of those things where you have to react quickly. They have the most sacks in the league, and I'm not sure how many for the four men up front. But I imagine it's quite a few."

It is actually 35 of the 42 sacks gobbled up by the defensive line, which means the Bengals are dangerous even when they play it straight. Against a rookie, however, it figures that Zimmer will throw some wrinkles his way.

"They do a lot of things with fire zones and blitzes that you have to be ready for, and I'm talking from a quarterback's standpoint and a protection standpoint," Reid said Tuesday. "This will be another challenge for [Foles] on a short week. It's one more step. Let's see how he does with it."

So far, Foles has taken each step asked of him, and his play has improved markedly in the last four weeks. On Thursday, with just three days of preparation, he will be asked to take an even bigger step - holding up against one of the best defenses in the league.

It could be a win-win for the Eagles. They might discover that they really do have a quarterback and, with the benefit of an up-close look, find the guy who can fix their broken defense at the same time.