The holidays were approaching, and 16-year-old Cameron Botticelli wanted a Christmas tree. He didn’t think that was asking his father for much — just a tree and some stockings, a few decorations to give the bitter home some normalcy.

Botticelli’s parents had divorced when he was 6. He and his baby sister lived with their mother at first, but she was a nurse who fell into addiction. So the kids moved in with their dad on Milwaukee’s blue-collar south side and hoped for the best.

By Botticelli’s sophomore year — three years before he followed his football passion to the University of Minnesota — the friction with his mostly absent father overheated. Botticelli wasn’t on speaking terms with his mother and detested his father’s girlfriend.

When his dad refused to get Christmas decorations, another heated argument ensued. Finally, after the holidays, his dad told him if he didn’t like living there, he should pack his stuff and leave.

“And so I did that,” Botticelli said this week, while preparing for the biggest game of his life. “I had just done laundry, so I grabbed a laundry basket and put it in the back of the car, and stayed for two nights in Marquette High School’s parking lot.”

It was January in Wisconsin, and the 6-5 future Gophers defensive lineman was stuffed inside his ’98 Geo Prizm.

“I remember it was cold,” Botticelli said, “because I woke up in the middle of the night to turn on the car and put on the heat.”

More than 2,500 nights have passed since then, and Botticelli hasn’t stopped dreaming of a better life after pushing himself relentlessly by day. An uncle basically adopted him that week and helped chart a new course. It was never easy financially, but Botticelli had brains and enough football talent to walk on at Minnesota.

On Saturday, the unsung defensive tackle and future lawyer will play his 50th game for the Gophers, with a chance to steal the Big Ten West title from Wisconsin. Botticelli and the Gophers will be a 14-point underdog at Camp Randall Stadium, which is fitting because that’s where he won a state championship for Marquette less than two years after those nights spent in the parking lot.

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After the second night in his car, Botticelli got a visit at school from his uncle, Jason Botticelli. The two already were close, having spent countless hours together around the man who remains Botticelli’s hero.

Dr. James T. Botticelli was a well-known Milwaukee cardiologist and a retired Brigadier General from the Air National Guard.

“My dad retired [from medicine] the day he found out he had lung cancer,” Jason said. “He survived 10 long years and was able to step back and enjoy his family and his grandkids. He had a remarkable bond with Cameron.”

In his paternal grandfather, Botticelli saw a man who had pushed himself to the top of his profession and had given back selflessly to his family. As a teen, Botticelli already had his hands full, helping raise a younger sister who felt just as lost without more support from their mom and dad.

Botticelli used to tote his sister to elementary school each morning aboard the pegs of his bike. He’d drop her off, then head across the street to middle school. When he was 14, Botticelli rode that same bike to his first job, as a cashier at McDonald’s, so eager he didn’t even mind the clip-on tie.

The idea of attending Marquette, a private high school, sounded outlandish to Cameron’s immediate family. But he passed the entrance exam with flying colors, and Dr. Botticelli footed the $10,000 tuition bill that first year, before Cameron got a scholarship.

When Botticelli’s relationships with his mother and father frayed beyond repair, Jason, the youngest of Dr. Botticelli’s eight children, stepped in to help.

“At that point, I was fed up with it all,” Jason said. “I dedicated my life to make sure that no one ever let down that kid again.”

Jason, 38, who has built a successful career in business development, told his nephew there would be no more sleeping in cars. The uncle recalled that pivotal talk: “I said, ‘I can guarantee you three things: a roof over your head, a couple of bucks to keep gas in your car to get you to and from school, and food in your belly.

“ ‘The commitment I need from you is that every step of the way, you improve from here going forward. We don’t take any step back, and we’ll go through anything we need to go through together. It’s us against the world.’ ”

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The family laid Dr. Botticelli to rest in April 2009. That fall, Cameron earned All-State honors as Marquette rolled through a 14-0 season. He originally committed to Illinois State but changed his mind the first time after winning the state title at Camp Randall.

“I saw the fans, and I saw the stadium, and I said, ‘If I’m going to do this, I’ve got to take my shot. I’ve got to play football at its highest level,’ ” Botticelli said.

He committed to Wisconsin as a walk-on, with plans to join Marquette teammates and twin brothers Michael and Marcus Trotter. Marcus is now the Badgers’ starting middle linebacker.

But Jason said he didn’t like the nonchalant vibe his nephew got from then-Badgers coach Bret Bielema. After a chance encounter between a family friend and Kevin Cosgrove, who was Gophers defensive coordinator then, Botticelli decided to check out Minnesota one week before signing day.

Tim Brewster was the Gophers coach, and Jason said Brewster was the first to sit down with his nephew and say: “Tell me about you. Tell me who you are.”

“And to my surprise, Cameron really opened up,” he said, “He’s always been very private about his childhood and the challenges of his mother and father. He told his story, and Tim Brewster put his hand on his leg and said, ‘You’re the type of man this team needs. This is a family. We want you to be a part of it.’ ”

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Botticelli was sold. He came to Minnesota as a two-star walk-on, but fueled by the anger of his childhood and a relentless drive, he started demolishing every three- and four-star offensive line recruit who stood in his path. He was named the team’s defensive scout player of the year in 2010, while redshirting, but then Brewster got fired.

Botticelli knew he’d have to prove himself all over again to Jerry Kill’s staff. He asked for his release so he could pursue other schools, but Dan O’Brien, Gophers director of football operations, wouldn’t grant it.

“I saw he had great potential from the day that he walked on here,” said O’Brien, now a senior associate athletic director. “He was a high-motor, try-hard kid, and that’s exactly what this program needs to be built on.”

Botticelli played in all 12 games as a redshirt freshman and continued proving himself the next spring before Kill gave him a scholarship. Botticelli started 24 games the next two years, playing in Ra’Shede Hageman’s shadow. This year, with Hageman in the NFL, Botticelli leads the defensive line with 7.5 tackles for loss.

“I can’t say enough good things about him,” Kill said. “Nobody talked about him a year ago because of Ra’Shede and so forth, but he’s been steady his whole career.

“He’s a tough kid. He dislocated an elbow when we were at Iowa [in 2012] and popped it back in, put a brace on and played. So he’s a throwback from the old days.”

Jason said his nephew has been driven by fear as much as anything.

“Every morning,” he said, “he woke up thinking that if he made a single mistake, he was going to lose his chance. He was going to lose everything he’d ever fought for.”

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Botticelli, a three-time Academic All-Big Ten selection, has an undergraduate degree in political science and is completing his master’s in youth development leadership. Though he knows he’s a long shot, he plans to see what NFL opportunities arise before heading to law school.

But first he has a score to settle with Wisconsin. He’ll be dressing in the same visitor’s locker room Marquette used to win its 2009 state championship.

“It’s fascinating to go back and think about it,” he said. “But the problem is, if you sit back and think about it too much, you lose your focus. I’ll save reminiscing for after the game Saturday.”

Botticelli remains close with his sister, who’s still in high school. He has reconciled a bit with his father but not his mother. On Senior Day, when the players went to greet their parents on the field, Botticelli came out and gave Jason a bear hug.

Asked what he’ll be thinking about this Thanksgiving, Botticelli paused for a long time before answering.

“I think about the opportunities that have been given to me and being able to capitalize on them,” he said. “There’s a stroke of luck in there, too. You could call that stroke of luck Jerry Kill, in how he honors the hard work of walk-ons. How he’s always quick to give someone an opportunity, when someone else might have written them off.”