There are but two scenarios under which Billy Donlon would've left Michigan.
One was another shot at head-coaching, and the other was Northwestern.
"Not only is that safe to say," Donlon said Monday. "It's true.
"For me, it wasn't about, you know, is this the best move of my career. I never asked that of myself. When I say that, it doesn't mean I'm not excited. This is a tremendous opportunity.
"This was about being home."
Donlon has been officially introduced as an assistant under Chris Collins at Northwestern, returning to the school where his dad coached from 1986-93 and where Billy was a ball boy well into his teenage years, as well as the city where he still has so much family.
Divorced and with an 11-year-old daughter, Maren, the family factor was a significant deciding factor.
Donlon's father, Billy Sr., as well as an older sister, still live in Northbrook, Ill., where Billy grew up. Donlon also played high school basketball at Glenbrook North High, in Northbrook, where Brian James was his coach. James also is on Collins' staff at Northwestern.
"We are obviously disappointed to be losing Billy. However, we are happy he has the opportunity to be closer to his family, home and still coach in the Big Ten," Michigan coach John Beilein said in a statement Monday.
"Over many years, Billy has sacrificed his family for coaching basketball. This time, he chose his family first, and no one can fault him for that."
Donlon, 40, spent one season at Michigan, joining the staff last summer after he was fired following a six-year run as Wright State head coach. He was axed despite 20-win seasons in each of his last four seasons, and immediately after an appearance in the Horizon League championship game.
He got the opportunity to stay in the Midwest after Michigan lost two assistants to head coaching jobs a year ago, LaVall Jordan to Milwaukee and Bacari Alexander to Detroit Mercy.
Michigan has two vacancies again, with Jeff Meyer joining Jordan's staff at Butler, and now Donlon heading to Northwestern.
Donlon's reputation is in defense, and that was his chief task with the Wolverines, who were third in scoring defense in the Big Ten in 2016-17, at 66.4 points a game.
They were sixth a year before, at 67.4 points. The increased aggressiveness and physicality, not charted in scorebooks, was more clearly evident.
Even in a short time, Donlon made a lot of memories in Ann Arbor, where the Wolverines finished 26-12. Following a scary plane mishap prior to the Big Ten tournament, Michigan went on to win four games in four days to win the Big Ten championship, then made the NCAA Tournament Sweet 16.
"I learned a tremendous amount from all aspects, from running a program to teaching and coaching, and then obviously you see leadership in action in an area there's probably no training for in the plane incident," Donlon said. "How well Coach Beilein handled that, but also how well the University of Michigan handled it, to the players and the families ...
"This was gut-wrenching for me."
At Northwestern, Donlon replaces Patrick Baldwin, who took over as Milwaukee head coach after Jordan went back to his alma mater, Butler.
The Wildcats are coming off a historic season, in which they were 24-12 and made the NCAA Tournament for the first time in the program's 116-year history. They also won their first NCAA Tournament game, 68-66, over Vanderbilt, before falling to top-seeded Gonzaga, 79-73.
Donlon will be part of a staff charged with getting back to the NCAA Tournament, a phrase he couldn't have imagined when he was sitting under the basket at Welsh-Ryan Arena, retrieving basketballs from age 9 through age 15 — long after most ball boys would've retired.
"It's a great opportunity," he said. "It's a great motivator."
Going from one elite academic institution to another, this will, remarkably, be Donlon's first time returning home on a full-time basis since high school.
For a man who lost his mother seven years ago, as well as an uncle and a brother-in-law in recent years, he's admittedly prioritizing the family he has left much more these days. He cringes to say he took family for granted, but it's moved way up on his pecking order, to be sure.
His daughter lives in North Carolina, but spends a lot of the summers with her dad — and, Donlon said, she called Ann Arbor the best place she'd ever been, because of how the Beileins, John and Kathy, treated her when she was around.
But Maren was home in Chicagoland this week, with her dad, and surrounded by family.
She called to tell her Mom, "Dad made the right choice."
"She loved the Beileins. She cried when she realized she won't see the Beileins on every trip. I love the Beileins," said Donlon, whose coaching career also has included stops at his alma mater, UNC-Wilmington, and American. "Then she got here and saw all the excitement with my family.
"And it really hit home. That's really what this is all about."