Sometimes it's easy, such as the past cases for Manti Te'o, Aaron Lynch, and Jaylon Smith. Sometimes the rookies come out of nowhere, and at a different position, to boot, a la Keivarae Russell and his transition from RB to CB in 2012. And sometimes it's the undersized three-star perceived to be the third-best among a trio of competitors at the same position.
Such is the case of Kolin Hill, the 230-pound, not quite six-feet-two inch pass rusher that has been in attack mode since his head coach put him in the game two weeks ago in a shutout victory over Michigan.
"My first couple snaps vs. Michigan, I was getting used to it. I was practicing at a good level in one-on-one pass-rushing so I knew I could make an impact in some way," said Hill of an evening that included a pair of tackles for loss including 1.5 sacks.
"It's a little surreal. I didn't have a lot of offers. I was underweight. Now that I'm here, it's a blessing. After the Michigan game, I got texts from my family, everyone that saw the game. It was unbelievable. My parents were really proud of me."
Surreal, perhaps, but Hill hardly seems overwhelmed by his early success.
"I'm a fast learner, but I'm still learning and still working on it," he said. "I just need to get my assignments and technique down. I make mistakes in the game like everybody else. There's nothing really difficult in the defense (for his job). I can get it."
Hill and fellow rookies such as Drue Tranquill, Andrew Trumbetti, Daniel Cage, and (former WR) James Onwualu "get it" because VanGorder has mandated it. The first-year Irish defensive coordinator was well aware his youth would be needed to augment the team's veterans.
"They really want their young guys to learn, they're really focused on the young guys," said Hill. "Coach VanGorder really stresses it, paying attention in practice. We're going to be here for the next 4-5 years so he wants us to learn."
To date, true freshmen Hill, Tranquill, Trumbetti and position neophyte James Onwualu have combined for 27 tackles including three for loss, with 2.5 sacks and a pair of official quarterback hurries. (QB Hurry is a statistic tracked inconsistently at best -- Hill alone has two per our film reviews.)
"It's great being on the team and being a freshman and contributing is a blessing too," said Hill. "I'm glad I made the decision to come here, playing for this historical program. (The adjustment) is from being the top dog in high school, coming here, you just have to have a role. I'm accepting my role, I'm a third-down guy. They utilize me as a pass-rusher."
Hill was withheld from the season-opener but was a key player in the defense's dime package one week later vs. Michigan. It wasn't a sudden ascent as much as a player earning his coach's trust.
"Retention of information. When we're going through our team work and they can repeat what we're asking them to do without making the errors," said head coach Brian Kelly of when a freshman is ready. "And Kolin knows what he knows relative to our third down package. When those freshmen get that knowledge base down, then we're ready to play him."
Hill showed his youthful wares once during the 31-0 victory over the Wolverines. Caught on the field due to an up-tempo change by Michigan's offense, Hill was unaware of his responsibility as a base 4-3 defensive end. The result was a nine-yard read-option keeper by QB Devin Gardner who ran behind the freshman as Hill charged down the line in pursuit of a running back -- without the football.
"I didn't know what personnel we were in and that messed me up," said Hill. "I know what to do now in that situation, it won't happen again. I had never had that before -- it was kind of embarrassing; panicked a little bit. I'm learning from it."
For the first time, Hill is learning from experiences without sharing them with his other half, twin brother Kaleb, a freshman at Boise State.
"Since we're at two different colleges we don't talk as much because we both have busy schedules," said Hill. "The time difference is also a challenge, Boise is about two hours behind us."
Kaleb is redshirting as a rookie defensive end for the Broncos.
"He got to watch the Michigan game. He's really happy. We both are competitive, so him seeing and watching kind of sucks for him because he wants to contribute to his team, but he's proud to see his brother playing."
Hill was certain he could contribute to the 2014 Irish cause. Notre Dame was in need of one, if not two edge rushers in VanGorder's scheme, an NFL-modeled approach in which "Rush End" is a starting position in the unit's myriad sub packages.
"Beating the guy who's in front of me was something I looked forward to," he said.
And something he's done to date.