JACKSONVILLE, Fla. -- After the past three weeks, Jacksonville Jaguars cornerback A.J. Bouye can’t help but wonder what happened.

How did Jacksonville's defense go from one of the league’s best in 2017 -- the dominant unit that nearly led the Jaguars to the Super Bowl -- to one of the worst in less than two seasons?

How did it become a defense that has given up four 200-yard rushing games, including three in a row to division opponents? One that has given up more than 20 first downs in seven games? One that can’t seem to make timely stops or create turnovers?

“I definitely do [wonder what happened],” Bouye said. “It’s a lot of things. But then you also have to look at it this way: Coming in, we expected a personnel that we didn’t get. We had one who requested a trade. We had one who never showed up at linebacker. Then you have Marcell [Dareus], who got hurt.

“We’re just trying to make it work with what we’ve got and it’s tough sometimes and sometimes we can’t adapt to it and we try to just stay within the scheme.”

The one who requested the trade was cornerback Jalen Ramsey, and when the Jaguars granted that request on Oct. 15, it became one of the most important factors in the defense’s sharp decline. He might have been disgruntled, a distraction inside the locker room and he might have found a reason to not play each week to force the Jaguars’ hand, but he was an elite player and not having a two-time Pro Bowl cornerback on the field put a major dent in the defense.

Ramsey was able to neutralize the opponent’s top receiver one-on-one when the Jaguars played man coverage, which was one fewer worry for the rest of the defense. He also was a willing tackler in run support near the line of scrimmage. He was the main source of the defense’s attitude and swagger in 2017 as well, and that’s another thing now missing from the unit.

Jaguars general manager Dave Caldwell was able to secure two first-round picks and a fourth-round pick from the Los Angeles Rams for Ramsey, though, and those additional draft selections will certainly play a large part in helping rebuild the defense.

The Jaguars need upgrades at every level of the defense. With Dareus not expected to be back because of contract reasons (he’s due to count $22.5 million against the cap with only $2.5 million in dead money), interior defensive line is arguably the team’s top need. South Carolina’s Javon Kinlaw and Auburn’s Derrick Brown are potential picks who could help immediately.

Clemson’s Isaiah Simmons and Oklahoma’s Kenneth Murray are two outside linebackers the team could target to play alongside Myles Jack. The Jaguars have a lack of quality depth at the position and likely would need to add another middle linebacker as well.

Safety is another major need. Ronnie Harrison (who likely won’t play this week because of a concussion) is in his second season as a starter, but Jarrod Wilson is a former undrafted special teams player who had started just two games in his first three seasons with the team before this season. The backups are undrafted rookie Andrew Wingard and special-teams standout Cody Davis, both of whom have struggled when they’ve gotten defensive snaps.

LSU’s Grant Delpit and Alabama’s Xavier McKinney are regarded as two of the top safety prospects and would immediately be an upgrade for the Jaguars.

But although the Ramsey trade is one of the main reasons for the defense’s decline, there are certainly other major factors:

Losing Marcell Dareus to injury

Dareus has been the key to the Jaguars’ run defense since he was acquired in a midseason trade from Buffalo in 2017. The Jaguars’ run defense ranked 30th in the NFL (138.6 yards per game) in Weeks 1-7 without Dareus. After the trade, they gave up only 98.9 rushing yards per game, which ranked eighth in the NFL in final 10 weeks of the season.

The Jaguars ranked 16th in the NFL in run defense last season and ranked 21st through the first seven weeks of this season (117.1 yards per game), which also includes a 285-yard performance in Carolina. Since Dareus went on IR with a core muscle injury on Oct. 25, the Jaguars have given up an average of 186.3 yards per game -- last in the NFL.

The Jaguars held the New York Jets to 46 yards rushing in their first game without Dareus, but have given up 200-plus yards in each of the past three games: 216 to Houston, 264 to Indianapolis and 219 to Tennessee.

Taven Bryan -- the team’s first-round pick last season -- started in Dareus’ place at three-technique defensive tackle in three of the four games (Calais Campbell moved inside from end to start the other) and hasn’t played anywhere close to the same level.

Cutting Malik Jackson and Tashaun Gipson

In March 2016, Jackson signed a six-year, $85.5 million contract ($31.5 million fully guaranteed and $42 million in total guarantees) with the Jaguars after four seasons in Denver. He set a career high with 6.5 sacks in 2016 and followed that with the best season of his career in 2017: eight sacks, four forced fumbles and his first Pro Bowl appearance.

However, he lost his starting job in November 2018 and his playing time decreased significantly in the final month, but he was effective as a third-down rusher. Cutting him saved the Jaguars $11 million this season. He's on injured reserve with the Eagles.

Gipson also signed with the Jaguars in 2016 and had six interceptions and 16 pass breakups in 48 games. His release saved the team $7.45 million.

The Jaguars drafted Bryan 29th overall in 2018 to be Jackson’s eventual replacement, but he struggled in a reserve role as a rookie (20 tackles, one sack in 286 snaps) and has just 18 tackles and one sack this season while playing 266 snaps through 11 games.

The Jaguars replaced Gipson with Jarrod Wilson, a former undrafted player who played in 47 games mainly as a special teams player in 2016-18. Wilson has started every game this season and has 49 tackles and two pass breakups.

Loss of LB Telvin Smith

Yes, Smith freelanced and had been out of position a lot. Yes, he was penalized for taunting too much. But he had elite speed, could make up ground and made a lot of big plays: nine interceptions (three of which he returned for TDs), 26 pass breakups, five forced fumbles and six fumble recoveries in 76 games. Per ESPN Stats & Information, he also had more solo tackles (441) than any player from 2014-18 and his 581 total tackles ranked fourth over that span.

That’s why his decision to not play this season for personal reasons was a huge loss for the Jaguars. Especially since their replacement plan was to draft Murray State linebacker Quincy Williams in the third round -- a move that surprised many, including other NFL teams.

Williams got hurt in camp, missed the entire preseason and started the first five games at weakside linebacker before being benched during the loss at Carolina as the Panthers were running for 285 yards.

Paul Posluszy's retirement

Posluszny was a tackling machine -- he’s second in franchise history (973) -- and was someone who knew the defense inside and out. He recognized the need for pre-snap adjustments, communicated the changes quickly and got everyone lined up correctly. Even when he was moved to strongside linebacker in 2017 so Myles Jack could take over as the middle linebacker, Posluszny still made the defensive calls because Jack struggled doing so. The Jaguars have not been able to replace Posluszny’s cerebral play.

Myles Jack's slump

The Jaguars signed Jack to a $57 million, four-year extension ($33 million guaranteed) before the regular season, making him the league’s third-highest-paid inside linebacker in terms of annual salary. He has 66 tackles (three for loss) and one interception in 11 games and has not shown a knack for diagnosing run plays. He has also struggled with his run fits.