Even though Allen was part of the No. 1 recruiting class that included Jahlil Okafor, Tyus Jones and Justise Winslow, he was the only one who wouldn't be starting. He wasn't even expecting to play a lot, considering Matt Jones and Rasheed Sulaimon were two experienced reserves ahead of him.
So when it came time for every player to meet with Krzyzewski and talk about season goals, Allen ended up with a most unique request.
The basketball-related matters were secondary, No. 1 on his list?
Whether in practice, on the bench or on the court, Krzyzewski wanted Allen to be outwardly active.
"I'm a really shy guy, and so when I first came here, maybe my quietness kind of overshadowed my enthusiasm," the 6-foot-4 Jacksonville, Florida, native said.
It didn't help Allen that Okafor, Tyus Jones and Winslow came to Duke having already known each other very well. They were all pretty familiar with how each other played, too. In that respect, Allen was initially on the outside of even his own class.
"It was a little different because me, Justise and Jah knew each other so well," Tyus Jones said. "But we quickly bonded and meshed so it didn't take too long to become extremely close."
It didn't take long for Allen to show the enthusiasm Krzyzewski was looking for, either. Both in practice and in games, Allen isn't afraid to speak up and assert himself.
He really can't afford not to anyway.
Duke's rotation is down to eight players. Its starters are responsible for the bulk of scoring and rebounding, but heading into the postseason, the Blue Devils know they're going to need the bench to come up with plays that turn a game in its favor. Allen is now showing he can provide that outburst.
"We've seen him do that time and time again in practice, where he cannot miss, and tonight, he had a great game where he was hitting shots and being aggressive," Tyus Jones said. "We all know that's the player he can be. He can come in and give us a great spark, and we'll need that come postseason."
Allen had already bested his season high of 18 points by halftime en route to a game-high 27 points on 9-of-11 shooting.
(Ironically, Okafor, the Blue Devils' leading scorer, had just six points. It was the first game this season he didn't reach double-figure scoring; that's how much of an aberration the blowout win was.)
"The bench played so well -- Marshall [Plumlee], Amile [Jefferson] and Grayson -- they played so well tonight," Krzyzewski said. "No matter who we had in the game, it was a very good functioning team."
Allen wasn't always functioning on that level. During the Blue Devils' first meeting with the Demon Deacons on Jan. 7, Allen played just one minute, had one turnover and never attempted a shot.
It was somewhat of a pattern for Allen to be absent from games. During the Blue Devils' first 20 games, he did not play in four and averaged just less than five minutes per game.
Allen has played in every game since Sulaimon's dismissal, and his minutes have nearly doubled to almost 10 per game.
"It wasn't really me waiting for a chance. It was just me being able to translate it in the game from practice," Allen said. "Coach has been giving me opportunities. I was able to capitalize today, and thankfully so. This is the kind of game that can get my confidence going."
Allen's 4-for-5 performance from the 3-point line moved his season percentage to 40.0, but what he was most excited about was getting on the boards. Of his four rebounds, two were offensive, and the only time he's had that many was against Furman.
"That's really what I want to do," Allen said. "I want to be able to crash the boards offensively and defensively, and just making little plays like that helps the team out."
At some point during the postseason, one of Allen's little plays just might be what helps Duke come up big.