Miami Dolphins running back Ronnie Brown was having a rough 2006 season until Sunday, when he ran through the Jets for 127 yards. That doesn’t mean Brown has turned his game around, though. It just means that the Jets’ run defense is playing the same way it has all year.

The Jets have played six games this season, and six times they’ve given up an opposing running back’s best game of the season. Prior to Brown’s performance during the Jets’ 20–17 win over the Dolphins Sunday, Jacksonville’s Fred Taylor, Indianapolis’s Joseph Addai, Buffalo’s Willis McGahee, New England’s Corey Dillon, and Tennessee’s Chris Brown have all had their most productive day of 2006 against the Jets. The Jets have allowed 872 yards on the ground this year, the secondworst total in the league, and they have given up 12 rushing touchdowns and 49 rushing first downs, worst in the league in both categories.

Although Brown had runs of 18 and 26 yards on Sunday, the biggest problem for the Jets isn’t giving up long runs. In fact, Brown’s 26-yard scamper was only the second run of 20 or more yards the Jets gave up this year. The real problem for the Jets’ defense is their inability to stop opposing running backs from consistently picking up a few yards at a time, especially in shortyardage situations. Brown twice gained first downs on third-and-short Sunday, and he scored a touchdown on secondand-goal from the 1-yard line.The average length of the 12 touchdown runs the Jets have given up this season is just four yards, and five rushing touchdowns have come from the 1-yard line. When a defense can’t stop the other team from getting one yard that means the defensive linemen are losing their individual battles with the opposing offensive line.

The defensive line’s inability to stop running backs shouldn’t come as a surprise to new Jets coach Eric Mangini because the run defense was the Jets’ biggest problem last year as well. Mangini thought he had taken a major step toward improving the defensive line when the Jets signed free agent Kimo von Oelhoffen to a threeyear, $9.2 million contract this off-season. The Jets figured von Oelhoffen’s experience playing in Pittsburgh in the 3–4 defense that Mangini runs would allow him to make a difference immediately. But von Oelhoffen looks out of place this year, and he hasn’t been nearly as effective as holdover ends Shaun Ellis and Bryan Thomas, who are learning the more versatile roles they’re required to play in Mangini’s defense.

Teams that use the 3–4 defense successfully usually have a huge run-stopping nose tackle who lines up opposite the center and keeps opposing linemen from blocking the linebackers behind him. The Jets don’t have any linemen who fit that mold. Mangini has Dewayne Robertson playing nose tackle, but Robertson would be better suited for end than tackle because he lacks the strength necessary to clog up the middle of the line.

In 2003, the Jets gave up two firstround draft picks to move up in the draft and select Robertson, and Robertson signed a lucrative contract that makes him one of the league’s highest-paid defensive linemen. The Jets haven’t had much of a return on their investment.

With Robertson struggling, the Jets should give more playing time to his backup, Rashad Moore, who at 6 foot 3 and 325 pounds is the Jets’ biggest defensive lineman. Moore made the most of his limited playing time on Sunday. In the third quarter he drilled Dolphins running back Sammy Morris to force a fumble, and his strength generally gave the Dolphins’ offensive linemen fits. Moore, a third-year player, signed with the Jets for the league minimum after being out of the league last year, but he looks like a better fit than the high-priced Robertson for the defense Mangini wants to implement.

The Jets would also be wise to give more playing time to veteran defensive end Bobby Hamilton, another new addition who has shown a clear understanding of his role in the 3–4. Hamilton spent seven seasons playing for Mangini during his tenure as an assistant, both with the Jets and the New England Patriots. Hamilton doesn’t make the spectacular plays that get defensive linemen noticed (he has only 19 sacks in his 12-year career), but he is a sturdy, dependable player who isn’t pushed aside easily on running plays.

Having Moore and Hamilton on the field would help inside linebacker Jonathan Vilma because both excel at controlling the offensive linemen in front of them. Vilma, the Jets’ 2004 first-round draft pick, is a very talented player, but at 230 pounds he can’t fight off offensive linemen who often outweigh him by 100 pounds or more. He needs defensive linemen to keep those blockers off him, and that is what Moore and Hamilton do best.

If the Jets’ run defense can make even modest improvements, they could be this year’s surprise playoff team. That says less about the Jets than about their schedule that is the league’s easiest down the stretch. Of their 10 remaining opponents, only three — Chicago, New England, and Minnesota — have winning records. Even though they’re only 3–3 now, a 10–6 finish and a chance at a playoff spot is possible.

But not if they keep giving every runner they face his easiest day of the year.

Mr. Smith is a writer for FootballOutsiders.com.