A'Shawn Robinson, the Lions' second-round draft pick last season, looks to have a bright future in the middle of Detroit's defensive line. Unlike most rookies, Robinson got better as the year progressed this past season, and finished first in the league among defensive tackles with seven passes defended.

"He's starting to make all the plays that show up, and obviously he hasn't scratched the surface yet," Lions head coach Jim Caldwell said of Robinson late last season.

After Robinson, however, the Lions are a little thin on both talent and depth on the interior of their defensive line.

Haloti Ngata, 33, is under contract for the 2017 season. He's still a load in the middle, but he's not the same disruptive player he was during his Pro Bowl years in Baltimore.

Tyrunn Walker and Stefan Charles, two key parts of Detroit's defensive tackle rotation in 2016, are both free agents, and Khyri Thornton, who was productive as a rotational player in the middle this past season, is a restricted free agent.

The Lions could certainly use reinforcements at defensive tackle, either through free agency or the draft.

While last year's defensive tackle draft class was one the best in the history of the draft, this year's crop of interior linemen isn't nearly as talented or deep.

With the NFL Scouting Combine kicking off next week, here's a look at some of the defensive tackles to keep an eye on during the week in Indianapolis:

MALIK MCDOWELL

School: Michigan State

Ht/Wt: 6-6, 276

Best trait: Athleticism. McDowell has a long frame, and moves more like a defensive end than a tackle. He has great size, strength and speed attributes. He can play both inside and outside in the NFL.

Concern: Some question his motor. Then there's the issue of his dramatic decrease in production from 2015 (13 tackles for loss and 4.5 sacks) to 2016 (seven tackles for loss, 1.5 sacks). An ankle injury suffered midseason in 2016 did play a factor in that.

The skinny: He's likely to test very well in Indianapolis, but the interview portion of the week will also be important for him. He's a terrific athlete that can play all over the line. He collected 90 tackles, including 24.5 for losses and 7.5 sacks, in 36 career games (23 starts).

CALEB BRANTLEY

School: Florida

Ht/Wt: 6-2, 314

Best trait: Strength. Guards and centers know they've been through a battle after playing against Brantley. He fits as a three-technique tackle, but is strong enough to probably play nose tackle as well.

Concern: He needs to be more polished as a pass rusher. He relies mostly on the bull rush, and will have to develop a better repertoire of pass moves.

The skinny: Brantley finished with 31 total tackles and led Florida with 9.5 tackles-for-loss and 2.5 sacks this past season. He has a really high ceiling if he gets better technique-wise, and adds more pass rushing moves to his game.

CHRIS WORMLEY

School: Michigan

Ht/Wt: 6-5, 297

Best trait: Production and versatility. He recorded 23.5 tackles for loss and 12.5 sacks his last two seasons at Michigan playing both inside and outside, which teams always like.

Concern: He's not an elite athlete. He relies on technique and a high football IQ to make plays. Will he be as productive against the NFL's elite o-linemen?

The skinny: Wormley was Michigan's Defensive Lineman of the Year in each of his last two seasons, which is saying something among that talented group. His coaches obviously love the way he plays. There's a spot for his kind of versatility in the right scheme.

CARLOS WATKINS

School: Clemson

Ht/Wt: 6-4, 312

Best trait: Playmaking ability. He led Clemson with 13.5 tackles for loss and 10.5 sacks in their run to the national title this past season. He also had 82 tackles from the interior, which shows both his athleticism and knack for the ball.

Concern: Playing strength could be an issue against the NFL's stronger interior offensive linemen.

The skinny: Watkins had a great year and followed it up with a good week down at the Senior Bowl. Some analysts wonder if he's strong enough to anchor and be a force in the run game in the NFL. The Combine testing will be important for him, but his production at Clemson is hard to ignore.

ELIJAH QUALLS

School: Washington

Ht/Wt: 6-2, 293

Best trait: He's a pure athlete. He rushed for over 1,800 yards and 23 touchdowns in high school as a fullback. He was a stand-up rusher at 300 pounds in the national semifinal game against Alabama. As expected, he's got great feet and quickness for the position.

Concern: Analysts have voiced concerns regarding Qualls' lack of core strength and length. He had a very modest 32 tackles, including five for loss and three sacks last season.

The skinny: It looks like he can play three technique or nose in the right scheme. He's nimble for a big man, but will have to get stronger to really take off in the NFL. A creative defensive coordinator can do a lot of things with Qualls.

DALVIN TOMLINSON

School: Alabama

Ht/Wt: 6-3, 312

Best trait: Drive. He could have gone to Harvard, but chose Alabama to play football. He worked his way up the depth chart after suffering a torn ACL as a freshman to play a key role in 2016, finishing with 62 tackles (5.5 for loss), three sacks and four pass breakups. He's a force against the run, as 55 of his tackles came against the opponent's rushing attack

Concern: Tomlinson suffered a torn ACL playing goalie on the soccer team as a senior in high school, and then tore an ACL again his freshman season. Medicals on him will be important. He was a starter for only one season.

The skinny: He was a three-time heavyweight wrestling champion in high school and plays with great leverage and power. He's strong against the run, and produced nice numbers overall, even though he was asked to do a lot of the dirty work in the middle of the Alabama defense.

JALEEL JOHNSON

School: Iowa

Ht/Wt: 6-3, 309

Best trait: Motor. Johnson has a relentless motor, which helped him earn All-Big Ten status by leading Iowa in both tackles for loss (10) and sacks (7.5) from the interior. 

Concern: Most scouts think he'll be a better pass rusher than run stopper, and will fit best in a one-gap scheme that utilizes that skillset. It narrows down the teams that might see him as a fit.

The skinny: He has the quickness and pass rushing ability to be a good fit in an attacking 4-3 defense at the three-technique.