ORCHARD PARK, N.Y. -- The Buffalo Bills have marketed their quarter-billion-dollar defensive line as the "Cold Front," and through six games this season, that moniker has been accurate -- just not in the way the team had hoped.

Despite Rex Ryan's reputation as one of the NFL's best defensive strategists, his defensive front has been frozen in place this season, and it's a growing problem. The Bills were held to just six sacks through the first five games and failed to register a sack of Andy Dalton in Sunday's 34-21 loss to the Cincinnati Bengals.

The Bills' switch from Jim Schwartz's defense to Ryan's coincided with diminished pass-rushing production from high-priced defensive ends Jerry Hughes, who signed a five-year, $45 million contract last spring, and Mario Williams, who signed a six-year, $96 million contract in 2012.

Both players walked a fine line when speaking to reporters after Sunday's game.

"Yeah, I'll let the coach coach, and we'll play," Hughes said when asked about Ryan's play-calling. "So whatever he runs, we'll run it."

"I think I probably set a record on dropping [back] today, but that's part of the scheme for us to go out and be put in a position to win," Williams said. "Whatever's called, you have to go out and do it."

Ryan took blame for the Bills' lack of pressure on Dalton, although it's hard to tell when Ryan is genuinely taking responsibility for a problem or simply trying to shield his players from criticism by bearing the load himself.

"A couple of them are my fault," he said. "I went with some three-man-rush stuff and never let my guys go as much as I should have.

"But I don't think our guys had enough shots on him, so we'll see. We gotta take a long, hard look at what we're asking our guys to do."

Time is starting to run thin for Ryan's defense to figure it out. The Bills (3-3) are almost halfway through their regular-season schedule and are quickly losing ground to two AFC East rivals, the New England Patriots and New York Jets. To make matters worse, Pro Bowl defensive tackle Kyle Williams was carted off with a knee injury and, according to a source, will miss the Bills' next game.

After the Bills dropped to 1-2 at home with a loss to the New York Giants, Ryan reassured fans that he would get the Bills' defensive woes squared away.

"I have been in this game a long time," he said Oct. 7. "I know where it is going to end up, but it is just we are not there yet."

Nearly two weeks later, the Bills haven't made progress. If anything, they've regressed. Ryan's confident stance that his defense would arrive by season's end now seems more like wishful thinking than a concrete plan on how to change the course of a faltering unit in a season that is beginning to slip away from the Bills.