After starting five sophomores and using nine freshmen on last year's defense that became attrition ravaged, Notre Dame defensive coordinator Brian VanGorder is expecting appreciable improvement in 2015.

"We're still young in a lot of places, so we're battling that," he said after Wednesday morning's practice, the fourth of 15 this spring. "As we grow the installs here, we'll be way ahead of where we were a year ago. … It was a little painful going through it, but it should pay off going into year two."

Along the defensive line, the blueprint looks something like this:

Strongside end: Isaac Rochell, Grant Blankenship and Jonathan Bonner.

Three technique/tackle: Sheldon Day, Jay Hayes and Micah Dew-Treadway.

One technique/nose guard: Jacob Matuska, Daniel Cage, Peter Mokwuah, Jerry Tillery and Jarron Jones, the starter who is not involved in contact while recovering from Lisfranc surgery.

Weakside end: Romeo Okwara, Andrew Trumbetti, Doug Randolph and Jhonny Williams.

Among those 15 scholarship players, only Day will be out of eligibility after the 2015 campaign. Eleven of the 15 have at least three years of eligibility remaining.

• Rochell is the "big end" in the base packages, but he will move inside in the sub packages.

"Isaac Rochell's improvements to me have been outstanding," VanGorder saidof the player with 39 tackles (7.5 for loss) and 10 QB pressures last season.

• Ideally, Cage, Hayes and Blankenship would have been redshirted last season, especially Cage at nose guard.

"Not only are they too young to be playing as they learn the game, but the volume of a season at the end of the year really showed on him, the wear and tear," VanGorder said of Cage. "He's a much better player right now, more confident. Still a long ways to go, but a lot of football in front of him."

• Among the 15 current freshmen, including the three early enrollees, Trumbetti (21 tackles last year, 5.5 for loss) is the standout.

"If there is any freshman that really jumps out, it would be him," said VanGorder, who has also praised the progress of early enrollees Tillery and Dew-Treadway as tackles, and Coney at Will linebacker.

"Not overwhelmed by the situation at all, not inhibited," VanGorder said. "They're competing. All three of them have been very surprising for freshmen."

• Speaking of freshmen, Williams has been classified as potentially the top speed rusher on the team, but he will need to progress much more before he can be a consistent contributor.

"We've got to get some more improvement out of Jhonny," VanGorder said. "Today wasn't a real good day for him. He's in that battle of process. … He's got a lot of work ahead of him."

Mike Linebacker: Nyles Morgan, Jarrett Grace, Michael Deeb and Joe Schmidt, Notre Dame's 2014 MVP who missed the final month because of a fractured/dislocated ankle.

Will Linebacker: Jaylon Smith and Te'Von Coney.

Sam Linebacker: James Onwualu, Greer Martini and Kolin Hill.

• A main item of speculation has been whether the crowded Mike position will see a shift of Morgan elsewhere, especially with the promising progress of Grace, who sat out the last half of 2013 and all of 2014 with a broken leg.

"His physical traits say he's more of a Mike linebacker than he is an outside linebacker," VanGorder saidof Morgan. "We have to get him a comfort level before we … we'd like to be able to cross-train linebackers. He's still in the learning process. We may experiment with that later when he gets comfortable playing Mike."

VanGorder doesn't anticipate that any of the linebackers will start cross-training until the last half to quarter of spring drills.

"As spring goes on, we'll work Jaylon around," he said. "Joe Schmidt will cross-train. He knows all the positions at linebacker."

• Count VanGorder among the believers now after having his doubts last year that Grace would ever be able to play again.

"He's been excellent," VanGorder said. "Very intelligent player. He couldn't play last year, [so] all he did was study, study, study … he knows our defense, he's way ahead of guys that have played because of that. He's an amazing guy."

• VanGorder echoed the platoon system at Sam linebacker with Onwualu and Martini that head coach Brian Kelly mentioned earlier this spring.

"James [is] closer to some of the qualities of a nickel physically, where Greer's maybe more suited for the core, when you have a tight end in the box and he could line up there," VanGorder summarized. "He's a little more effective there with a little longer arms and bigger body than James.

"James is kind of a compromise nickel in some ways. He can't do all the things in terms of manning a wide receiver, but he can cover down and be effective there."

Cornerback: Cole Luke.

Cornerback: Devin Butler and Nick Watkins.

Strong Safety: Elijah Shumate, John Turner and Drue Tranquill, who is recovering from ACL surgery performed in November.

Free Safety: Max Redfield, Matthias Farley (nickel) and Nicky Baratti, who has been cleared after missing almost all of the past two seasons because of three shoulder surgeries.

• Farley is cross-training at safety because of the shortage there, but will remain the primary nickel. Senior walk-on Eamon McOsker has received some reps although he did have a hamstring injury. Farley actually began re-training at safety (where he has 19 career starts) late last year.

"A reliable, dependable player," VanGorder said of Farley. "He was a little rusty, so we've got to get him fine-tuned this spring and get him more reps at safety. He will still play nickel for us. … The main two traits he gives us: He can play the run game and he's smart."

• VanGorder said there a lot fewer "panic snaps" from the safety tandem of Redfield and Shumate, who had roller-coaster campaigns last season.

"They've been real solid so far, way more comfortable, way more knowledgeable," he said. "The consistency of the position and the comfort of the position will bring out more of those physical traits that they have and make them more productive. They have to keep working."

• Although cornerback might have a safety net with the expected re-admission of KeiVarae Russell this summer to team with Luke, whom VanGorder has lauded, he wants to see much more from Watkins while he tries to push Butler for a top spot.

"Last couple of practice Nick's been better," he said. "He had a rough start … but he seems to have a better attitude than he did when he came in as a freshman. He was kind of one of the freshmen that couldn't really find himself last year."