Loaded DT class offers chance to replace Raji

College football’s influence on the NFL is easy to see. The game’s evolution has altered positional responsibilities, changing which kind of prospects enter the draft each spring.

Tight ends are more receivers than blockers. Linebackers are more third-down pass defenders than first-down run stoppers. Safeties either possess a cornerback’s skill set in coverage, or they’re hybrid linebackers who play strictly in the box.

It is no longer a game exclusively won or lost in the trenches. Each year, success depends more on how players perform in space. So the 2016 NFL draft may be a fluke. A one-year aberration. Because this year, with spread offenses never more influential, the draft’s deepest and most talented position is defensive tackle.

“It’s a really strong group,” Senior Bowl president Phil Savage said. “It’s sort of interesting that it’s happened this way because, with the spread and all the things that happened in college football, you might’ve thought maybe they would move away from defense. But there’s a slew of defensive linemen this year.”

Related: Complete Packers draft coverage

2016 NFL draft: Top 10 defensive tackles

There are too many defensive linemen to name each one in a preview of this year’s defensive tackles. The best way to describe this class may be comparing round by round. In the draft’s third and fourth rounds, NFL Network analyst Mike Mayock said, teams will be able to take defensive tackles that would be selected in the first and second rounds most years.

“It's a defensive draft,” Mayock said. “Best interior defensive line I've seen maybe since I've started doing this.”

The Packers were blindsided when B.J. Raji prematurely retired earlier this offseason. His departure from the game increased the urgency of upgrading the Packers' defensive line. Turns out, they were fortunate Raji retired this year. General manager Ted Thompson will have plenty of options to pick from.

It’s hard to determine which area requires more improvement: defensive tackle or five-tech defensive end. Either position not occupied by three-tech defensive end Mike Daniels should be considered a need. In today’s league, special attention should be given to bolstering a defensive line’s collective pass rush.

With Letroy Guion showing more ability rushing the passer from the interior in 2014 than defensive end last season, his best position may be nose tackle. If Guion returns to the interior, that could make five-tech defensive end Thompson’s preference in the draft. Former undrafted defensive lineman Mike Pennel figured to be the Packers' starter across from offensive tackles in their base defense, but he’ll miss the first four games next season after being suspended for violating the NFL’s substance-abuse policy.

Alabama’s defensive lineman A’Shawn Robinson isn’t likely to be available when the Packers are on the clock with the 27th overall pick, but he would be an ideal choice. Robinson brings positional versatility at 6-foot-3⅝ and 307 pounds. His 34½-inch arm length and 83½-inch wingspan give him the length to play five-tech, where he lined up for the Crimson Tide. Robinson also can line up inside.

As the draft approaches, there are concerns whether Robinson can be a productive NFL pass rusher. He had 3½ sacks last season as a junior, not the numbers expected for an elite prospect. Savage, a former Cleveland Browns general manager and longtime Baltimore Ravens executive, watched Robinson up close for three seasons as a color commentary for Alabama football on the program’s flagship radio station. He said Robinson has “untapped athletic ability” that could help him develop into a pass rusher at the next level.

“'Bama is a two-gap team by nature,” Savage said. “So he didn’t have a lot of freedom to get upfield and going after the quarterback. But in saying that, he’s almost 6-foot-4. He’s 310 or 313 pounds, whatever he is. He’s also only 21 years old (just turned 21 in March). So to think what he could be a year from now, I don’t see how in the world he would get out of the top 15, certainly not the top 20.

“I don’t think they give those inside guys a ton of freedom to just one-gap and go and get up the field.”

Robinson’s teammate on Alabama’s defensive line is more likely to slip to the late first round.

Jarran Reed, a former junior college transfer, might be the best run defender in his defensive line class. He has some positional versatility at 6-foot-2⅞ and 307 pounds, though he’s not as suited for five-tech defensive end as Robinson. Reed’s 33⅜-inch arms and 81⅛-inch wingspan don’t provide the same length against offensive tackles.

Savage said Reed could develop into a pass rusher capable of recording three or four sacks a season, a consistent pocket pusher. It never will be his strength. Reed was a more “steady” player than Robinson at Alabama, Savage said, but Robinson’s upside could give him an advantage.

“In the top half of the first round,” Savage said, “you’re rolling the dice a bit that you’re hoping to hit on a Pro Bowl-level player. I think Robinson has got that kind of potential.”

There’s a long list of potential impact players beyond the two Alabama linemen. None has more upside than Louisiana Tech’s Vernon Butler. Another prospect with positional versatility, Butler eventually may find a home at five-tech end. At 6-foot-3⅝ and 323 pounds, he’s even longer than Robinson with 35-inch arms and 83⅞-inch wingspan.

Butler plays with good leverage, allowing him to get under blockers and generate a powerful bull rush. With explosive quickness off the snap, he could also develop into a consistent gap penetrator. He has underdeveloped technique, and Savage said Reed would be a “safer” pick than Butler. But Butler’s potential could slip him into the first round.

“Many people see him as having a real high ceiling,” Savage said. “He’s got first-round natural talent, but he’s got more second-round production and background and those sort of things. I think there’s a chance he goes in the first round. If not, he’ll go pretty early in the second. You’re better on the rise with him, that once you get your hands on him he’s really going to elevate his game.

“I think if a team is looking for somebody to play right away, they would lean toward Reed. If a team is thinking that they could develop Butler, there’s certainly a chance of that happening.”

Without Raji, the Packers could emphasize bolstering their run defense. Raji was an enforcer in the trenches. He provided little pass rush, but his ability to consume blockers made his teammates better.

If Reed is the best run defender in this defensive line class, Baylor nose tackle Andrew Billings isn’t far behind. Billings is a true interior lineman, short and stocky at 6-foot-⅝, 311 pounds. He doesn’t have much length (33-inch arms, 79-inch wingspan) for shedding blockers, which could limit his ability to pressure quarterbacks.

But Billings is as strong as any prospect in his class, benching 31 reps of 225 pounds at the combine. His strength allows him to push the pocket against the run and pass. With further development, he can fill the nose tackle position in a 3-4 base defense for a long time.

“Billings is as good a run defender as there is in this draft among all the defensive tackles,” Mayock said, “and the two Alabama kids are outstanding with that. Billings is outstanding. He needs to get a little bit better at rushing the quarterback because it's a pass-first league. And if you're only playing 30 or 40 percent of the snaps, your value goes down a little bit.

“So for Billings, you could place a first-round talent on him or first-round grade on him, but he's either going to go late (Round) 1 to mid-(Round) 2? And if he goes in the second, it's going to be just because teams are worried about how many snaps he's going to get the first couple years in his career.”

rwood@gannett.com and follow him on Twitter @ByRyanWood

MARKET WATCH

Rising stock: Mississippi State defensive tackle Chris Jones underperformed in college, but the former five-star prospect’s raw talent could shoot him up draft boards.

Falling stock: Ole Miss defensive tackle Robert Nkemdiche is the most physically gifted prospect in his class, but character issues off the field and inconsistent play could drop him to the second round.

Sleeper: Notre Dame defensive tackle Sheldon Day might not be drafted until the third round, but he has drawn comparisons to Packers defensive end Mike Daniels as a quick and undersized prospect who can develop into an active pass rusher.