Sheldon Richardson

Sheldon Richardson isn't pleased with how the Jets' defense has played this season. (AP Photo | Julie Jacobson)

FLORHAM PARK -- Through four games, the 1-4 Jets' defense barely resembles the group that thrived last season, and was expected to do so again this year.

Let's compare some numbers.

Last season, the Jets finished fifth in Football Outsiders' defensive DVOA. This season, they are 30th.

Last season, they ranked third in takeaways, with 30. This season, they have the NFL's second-fewest (four).

Last season, they were third in third-down defense and first in the red zone. This season, they are 13th and 15th.

And last season, they had the league's sixth-best quarterback rating allowed. This season, they have surrendered the highest quarterback rating so far.

Defensive end Sheldon Richardson told NJ Advance Media the Jets are "not even close" to as effective as they should be.

He was talking specifically about third-down defense, but the assessment works for the defense as a whole. Except for the run defense, which ranks second in the league in yards per carry allowed.

"That's about it, though," Richardson said. "It's surprising that we're not doing a lot. It's surprising that we're 1-4."

During the Jets' current three-game losing streak, opponents have converted 15 of 35 third downs (42.9 percent). And that includes a 3-of-10 showing by Seattle. The Jets last season allowed a third-down conversion rate of 33.2 percent.

"We should be better than what we're doing," Richardson said. "I know it's new to some guys, but some guys are making plays and some guys aren't. Some guys are trying to do too much and hurting the defense."

The Jets haven't gotten enough lately from their pass rush, as opposing quarterbacks are getting the ball out quickly -- a reaction to what the Jets did in their opener.

The Jets had seven sacks in Week 1 against the Bengals. In four games since, they have five total sacks -- and a sack percentage of just 3.4. Last season, the Jets' sack percentage was 6.1.

"As a defensive lineman, it's hard to counter that," Richardson said of the quick-passing approach. "It's really impossible for you to get a pass rush when it's a catch-and-throw [approach]. Very frustrating. But you can't hang your head down on it. You've got to do something to stop it."

The Jets' opponent on Monday, the Cardinals, typically likes to throw a lot of deep balls, which means their fairly immobile quarterback, Carson Palmer, will probably stand in the pocket for longer. Which could mean more sacks.

Plus, the Cardinals will be without both of their starting offensive guards, Evan Mathis and Mike Iupati, on Monday night.

Jets defensive coordinator Kacy Rodgers isn't down on his defensive line, despite the lack of recent production. But he knows it must perform Monday.

"I thought they might be the best position playing on our team," Rodgers said. "If we can't get to [Palmer], it could be a long day for us, because obviously we anticipate them going down the field on us, because that's what they do."

In Richardson's harsh assessment that some Jets defenders are trying to do too much, he said, "that's myself included in that."

During film study, he noticed instances when he'll pull back on his pass rush too quickly -- to go pursue the ball -- because of how fast quarterbacks are releasing the ball. Richardson said he can't let up in his pass rush.

"I should be rushing," Richardson said. "There are some times when I actually caught myself dropping back. I got used to turning and running so much, and I got pump faked. And then I turned around and [the quarterback] still had the ball. I could've had a sack on that one."

Darryl Slater may be reached at dslater@njadvancemedia.com. Follow him on Twitter @DarrylSlater. Find NJ.com Jets on Facebook.