Jefferson started seven games last season after an injury sidelined senior Ryan Kelly. Before then, Jefferson played limited minutes and admitted to some frustration but said he got a chance to learn a lot.
That was the 200-pound Jefferson. He is listed at 210 this season but figures he is up to 216.
In addition to more weightlifting, Jefferson's offseason diet called for food "at all times, even sometimes when you're not hungry," he said. "Just realizing you haven't eaten in two hours. It's a challenge. Constantly eating and instead of eating a light meal, go get the burger the mashed potatoes, the fries. After that, you might get a protein shake. Start doing that again two hours later."
He's burning off plenty of calories this season. With new personnel, Krzyzewski has a new game plan featuring more up-tempo play and plenty of full-court pressure.
"You can't practice the same," Jefferson said of the new plan. "We had to focus on being in much better shape. We were in amazing shape. We have to be players who almost never get tired."
Duke's coach said he has seen Jefferson make all sorts of strides. With this group, Krzyzewski said, Jefferson is allowed "to just be a player," not typecast into a specific position.
"What is he? A [power forward or a center]? I don't know," Krzyzewski said. "I think he's just a good player. . . . I think he's got an unbelievable personality to play the game, an exceptional personality to play the game."
By that, Krzyzewski said, he meant Jefferson isn't bothered by anything on the court.
"He's such a good teammate, and he's got a 7-2 wingspan," Krzyzewski said. "When you position a guy, you look at their strengths and weaknesses. . . . When you don't position guys, you mostly look at their strengths. I'd rather do that. What do you do well? Do what you do well. Don't try to do what you don't do well. And let's try to figure that out."
Krzyzewski isn't saying anything is cast in stone when it comes to playing time.
"It will be very fluid," he said. "Guys have a good week or two weeks, you go with that, or even within a game."
Jefferson clearly is starting the season in his coach's good graces. Playing 21 minutes in Duke's last exhibition game against Division II Drury, Jefferson had 13 points and 16 rebounds.
In Duke's opener, a 111-77 rout of Davidson, Jefferson had 10 points in 11 minutes. He gets his role.
"I definitely knew that I would have an opportunity to help this team out, in some way or another," Jefferson said.