Head coach Jim Caldwell is up front about where the Detroit Lions' defense has to get better.

Big-play production dropped off dramatically last year, and a lot of it had to do with the front seven. A lot falls on the shoulders of the defensive line in the Lions' 4-3 base scheme to create pressure that causes sacks and turnovers.

A draft deep in defensive tackles and edge rushers gives the Lions an opportunity to add talent and depth from the first round on down.

"We've got to become more effective," Caldwell said at the recent League Meeting. "We've got to make it happen. We've got to get the ball turned over more often."

The Lions fell from 43 sacks in 2015 to 26 last year, tied for second fewest. The defense forced only 14 turnovers – 10 interceptions and four fumble recoveries. Only the Bengals, Browns and Bears had fewer recoveries, with three each.

D-line draft priority: High for an edge-rusher.

Lions DL Draft Breakdown: Depth chart, stats, capsule highlights of the top 5 DE and DT prospects, other notable prospects and the Spotlight Player.

Youth movement: Kerry Hyder started strong as a pass rusher last year, and rookie tackle A'Shawn Robinson finished strong. Robinson could anchor the interior for a decade.

"He really was getting better and better and better," Caldwell said. "He has just a great knack from a schematic standpoint of playing behind his pads. He's really starting to come on."

Hyder, who was promoted from the practice squad late in 2015, had a team-high eight sacks. Seven were in the first nine games.

Free-agent impact: Players added or re-signed were for depth.

Depth chart: Returning starters – DE Ziggy Ansah, DTs Haloti Ngata and A'Shawn Robinson. Returning backups – DE Kerry Hyder, DE Anthony Zettel, DE Armonty Bryant, DE Brandon Copeland, DT Khyri Thornton. Additions: DE Cornelius Washington, DT Jordan Hill, DT Akeem Spence.

Sack stats: The Lions and Browns were tied for next-to-last in the league with 26 sacks each, one more than the Raiders. Kerry Hyder led the Lions with eight sacks. He had five in the first three games and seven in the first nine.

**Top 5 defensive ends:

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1. Myles Garrett, Texas A&M: The consensus pick to be drafted first overall by the Browns, his workout lit up the Combine – 4.64 in the 40, 33 reps in the bench press, 41-inch vertical jump. At 6-4, 272 pounds, he has the stature to dominate. As a high school player in Texas he was one of the top prospects in the country and continued to excel in college.

Stats line: Garrett set the SEC for sacks by a freshman with 11.5 in 2014 and followed that with 12 in 2015. Injuries limited his playing time and availability in 2016. He finished with 8.5 sacks in 10 games.

2. Solomon Thomas, Stanford: A fast riser who could be the second player off the board to the 49ers, barring a trade. A notch below Garrett physically, but an excellent athlete in his own right. He was a red shirt as a freshman in 2014 but played all 27 games his last two seasons.

Stats line: 25.5 tackles for loss, including 11.5 sacks in 2015-16 combined. Thomas does not turn 22 until December.

3. Derek Barnett, Tennessee: Not the ideal build for the position at 6-3, 259, combined with a 4.88 time in the 40 and a 31-inch vertical at the Combine. However, his production is there to be taken in the first half of the first round. He was the first defensive lineman in school history to start on opening day as a freshman.

Stats line: A highly productive three-year player – 52 tackles for loss, including 32 sacks to set the school record, formerly held by legendary Reggie White.

4. Taco Charlton, Michigan: Good size (6-6, 277) and strength (25 reps in the bench press) for a player with an arm length of 34-plus inches. He'd fit in well for the Lions at left end as a player who could set the edge to defend the run. Charlton was an ascending player throughout his four years at Michigan, becoming a full-time starter in 2016.

Stats line: Set his career highs in 2016 with 13 tackles for loss and 9.5 sacks.

5. Charles Harris, Missouri: It's a close call between Charlton and Harris. Charlton is bigger and stronger than Harris (6-3, 253), and with a little more explosion, but Harris is a little quicker. Harris was a three-year player at Missouri after a red-shirt 2013 season. He also played wide receiver and basketball in high school.

Stats line: 30.5 tackles for loss his last two years, with 16 sacks.

(Note: Takkarist McKinley of UCLA and Tim Williams of Alabama are listed in some rankings as defensive ends and as linebackers in others. They are linebackers in this series.)

Top 5 defensive tackles

1. Jonathan Allen, Alabama: The Crimson Tide roll out high-quality defensive linemen the way Apple rolls out iPhones, and Allen is the latest off the assembly line. Allen is on the light side for an interior defender at 286 pounds, but he's athletic enough to play defensive end if needed.

Stats line: A four-year player, Allen had 44.5 tackles for loss with 28 sacks.

2. Malik McDowell, Michigan State: A celebrated high school player who grew up in Detroit and transferred to Southfield High School for his senior year. McDowell is a big man (6-6, 295) who is quick enough to line up at defensive end in some situations. Some question his effort, but the ability is there. Talent has exceeded production.

Stats line: A three-year player and a starter the last two, 2015 was his best season – 14 starts, 13 tackles for loss with 4.5 sacks.

3. Caleb Brantley, Florida: A solid three-year player after a red-shirt season in 2013. By all indications he plays better than his workout results would indicate.

Stats line: 8.5 tackles for loss and 2.5 sacks in 10 starts in 2016; 6.5 tackles for loss and 3 sacks in 10 starts in 2015.

4. Chris Wormley, Michigan: A four-year player and a 2012 red shirt because of a knee injury sustained in training camp, Wormley worked his way into a full-time starting role his last two years. Wormley was elected a team co-captain along with tight end Jake Butt in 2016 and was voted first-team All-Big Ten in 2016.

Stats line: Wormley finished strong, with 9.5 tackles for loss and six sacks, second most on the team.

5. Larry Ogunjobi, Charlotte: An excellent student, whose family moved to Charlotte from Nigeria. He had a double major in computer science and biology. Ogunjobi was awarded the honorary No. 49 jersey – symbolizing the Charlotte 49ers – for their inaugural season of football in 2013. He started all 46 games in four years.

Stats line: 49 tackles for loss and 13 sacks for his four years, with a one-game high of 4.5 tackles for loss vs. Florida International.

Spotlight – DT Ryan Glasgow: Football doesn't run in the Glasgow family. It blocks and tackles. Ryan's brother Graham was a starter on the Lions' offensive line as a rookie third-round draft pick in 2016 out of Michigan.

Ryan was a four-year letter winner at Michigan and earned the Katcher Award in 2016 as the team's top defensive lineman. Ryan had 9.5 tackles for loss with 4 sacks in 2016.

Younger brother Jordan played 13 games at safety for the Wolverines as a sophomore in 2016.