In the moments before Gorilla entered the boxing ring, he paces the floor, terrified for his future.

A four-months-old Achilles’ tendon injury is hurting, much more so than he is letting on to anyone outside his inner circle.

“I was going in there blind,” said Aaron “Gorilla” Green, a gentle giant inside a hulking 6-4, 275-pound frame. “I didn’t want to show it, but … I didn’t know what to expect.”

But Green, an up-and-coming boxer in Minnesota at age 31, has become accustomed to chaos. He takes a deep breath and heads toward the spotlighted entryway, knowing this is just another exacting leg in the journey — one impassioned man’s struggle to make his mark in an industry that routinely chews up and spits out its eager participants.

At Hinckley’s Grand Casino Friday Night Fights this past weekend, one professional boxer was significantly battered in a lopsided fight, taken simply for the money. Another was led away by police; with a warrant for his arrest, the promotion posters gave officers the only lead they needed. Like most fighters in this stage of their careers, Green’s body is hurting. He’s tired. The Golden Valley resident toils through a second full-time job — working security overnights — to make ends meet.

Physical, financial and emotional aches are steppingstones to the glory many dream about, but few have the dedication, talent and toughness to realize.

After another victory, his squinty-eyed smile returns in full force as Green — now 12-0 with 10 knockouts as a professional — practically bounces around his designated locker room. In one of the most dangerous, difficult and unrewarding sports, nothing is for granted, even for the smartest athletes.

For Green, it makes it all the more worthwhile.

Career transition

One February night in 1990, a young Green was planted on the living room couch in his family’s Hinsdale, Ill., home, unable to believe Mike Tyson, his boyhood idol, could lose. Tyson did lose that night — in a memorable bout against Buster Douglas — but it only further drew Green to the sport’s excitement. Boxing became an obsession, but stayed just that with most of Green’s free time taken up by basketball, the sport he would play in college as a scholarship athlete.

Seventeen years later, Green was 25 and a recent college graduate, working as a personal trainer at a local gym. A pair of fighters who occasionally trained there rekindled the boxing flame, and after talking to them, Green started taking a weekly hourlong beginner class. The more he did it, the more he loved it. Outside the ring, he was understated and soft-spoken. Inside the ropes, he got to be a different person.

Eventually, organized fighting made sense. Green’s wife, Frances, a former Division I golfer, understands competitive desire, so they never had an official conversation about his transitioning career. It just began.

Green’s first two amateur matches were held at Uppercut Boxing Gym in northeast Minneapolis, where he now trains. In the second, Green knocked out his opponent in only three rounds. Afterward, Lisa Bauch — Uppercut founder/owner and now a member of his team — approached Green’s trainer at the time, demanding to know just how many fights his pupil really had.

After grilling Green and his trainer, Bauch’s anger turned to astonishment. Was it possible he’d only had one previous fight?

“And if that’s the case, we need to get him here,” she said.

Double life

At 11 p.m. on a typical Thursday night, Green is behind the front desk of the DoubleTree hotel in St. Louis Park, glancing down at a clipboard full of notes.

“Time to lock this place up,” he says.

Looking like the Clark Kent version of Superman — in a black suit and tie with black, thick-framed glasses — Green strides through the building. Monday through Friday, he’ll work here until 7 a.m., fighting off sleep rather than punches. Often, when day breaks and his shift is over, Green will head directly to the gym to spar.

His salary from DoubleTree, combined with the one Frances makes as a consultant for 7 Medical Systems, helps the two live comfortably in a modest apartment. Since going pro in October of 2010, Green has averaged about four fights a year and makes anywhere from $2,500 to $4,000 at each event. Some of that is contingent on selling the ticket allotment the promoter gives him — typically around 100-150.

Percentages of the purse go to Bauch; Pete Daszkiewicz, his head trainer and son of legendary Minnesota boxing trainer/manager Papa Joe Daszkiewicz; and Heath Roth, his co-trainer. The rest is mostly used for travel, equipment and doctor bills. But even if Green’s boxing career someday becomes profitable, which he anticipates, he still has no plan to quit his night job.

Before all this, Green swears, he wasn’t quite so tough.

“If you can do that, you can do anything,” Frances said. “The mental toughness that he’s had to go through the last couple of years, doing that schedule, you can’t get that anywhere else.”

In the DoubleTree, Green locks the double doors to Terrace Ballroom 1, grins and slowly turns back.

“I’m kind of a sucker for pain,” he said.

No more quitting

Former North Dakota State assistant coach Todd Koering still laughs when he remembers Green approaching him with his plea to play point guard. Even in basketball, he wanted control.

Basketball probably contributed to his excellent footwork and gave the first hints of his toughness — in the post, Green would take elbows to the face and shrug them off. But after three seasons, Green’s frustrations with the team were too much for him to handle and he left.

“He’s so internally motivated, so intrinsic,” Koering said. “He was the guy that sometimes we would say, ‘I don’t know if basketball is good for him’ because you have to tolerate teammates and coaches and opinions and direction that maybe he didn’t totally agree with.”

Green transferred to South Dakota State with a new vision, but the frustrations remained. One day during a practice, Green got mad and simply walked out. Later, regretting his temper, he returned to practice — but the coaches told him he wasn’t welcome back. Green swore he’d never quit anything like that again.

Ready for battle

Three hours before striding out to the ring Friday, Green — sporting a new fauxhawk haircut — sits elbows on knees, head in hands, intently watching film of opponent Stacy “Bigfoot” Frazier on Daszkiewicz’s laptop. Daszkiewicz sat next to him, Bauch knelt behind; both offered analysis.

“He’s sloppy with that left hook,” Daszkiewicz said. “It’s his favorite punch, but he’s sloppy with it.”

Later, at the casino, three boxers and their entourages cram into one locker room. Green chooses the short hallway between the bathroom and the lounge as his territory: earbuds in, jogging in place, squatting, stretching, mostly pacing.

Daszkiewicz drops the gauze he’s laying out to wrap Green’s hands — a good-luck charm, he says. Every time he’s dropped the gauze on a fight night, Green has knocked out his opponent. Still, everyone is nervous. No one wants to let on, but everyone is feeling it.

In April, Green tweaked his Achilles’ tendon. A $300 out-of-pocket experimental treatment that was supposed to help him recover in six weeks has not worked. The problems have only compounded, creating a host of other issues.

“I thought I was going to have to end my career,” Green said. “I kept telling Pete, ‘I don’t know if I should take this, I don’t know if I should take this.’ ”

But fresh in his mind is the promise he made to himself years ago.

“I can’t quit,” he said.

In the ring

At the opening bell, Frazier comes in throwing punches. Green cups his gloves at his nose, deflecting the attack. He always spends the first round feeling out his opponent, but in this bout, his trainers are especially sensitive to early signs. Frazier is the aggressor; Green is retreating. Several rows beyond the ropes, a tall, blonde figure is standing, sticking out from the crowd.

“Keep those hands up, keep those hands up, watch the left hook!” Frances screams.

But midway through the fourth round, the momentum switches. Green lands two right hooks; Frazier’s pants are falling off. They dance to the middle before Green works his opponent into a corner. A right jab to the face connects; it’s enough to stun Frazier for a second, which is all Green needs.

He starts the battering — 19 punches before a bruised Frazier is able to escape. Before the fifth, referee Mark Nelson warns Frazier to show him something if he’s to keep the fight going. But Green attacks again, delivering a devastating blow to the liver. Frazier wails, and Nelson comes running in to stop the match as Green, smiling for the first time, lifts his gloves and gallops around the ring in victory.

Afterward, a combination of relief and exhilaration overwhelms the locker room.

“I was scared,” Daszkiewicz says. “I was scared because I knew that Aaron wasn’t comfortable with where he was at with that injury, and he was questioning himself.”

When the celebration calms, Daszkiewicz clears his throat.

“I wasn’t going to mention this before,” he says. “We’ve got a chance to fight on Sept. 21 up in North Dakota, and I’m going to say no.”

Green, who has consumed so many 5-hour Energy shots he surely wouldn’t sleep, shrugs. “I don’t know,” he says. “I think I might be fine.”

Daszkiewicz can only shake his head.

“You see this?” he says, half-incredulous, half-impressed.

A couple of hours later, as Bauch drives back to the hotel, she looks realistically at the fight offer and Green’s injury. “I don’t want him to take it,” she says. “It’s too soon.”

So much of Green’s future is still unsure, although promising. He’s built a foundation around his career; a barrier so that he’ll never have to take bad fights, as some boxers do. Still, there’s the call of passion, an obsession that never goes away.

“Probably the worst disease a person could ever get is the love of boxing,” Daszkiewicz had said earlier.

Green is infected. But in the moment, anyway, he doesn’t want a cure. Back in the locker room, red welts gracing his forehead, he struts around, with more spring in his step now than seems possible.

This feeling is the only thing boxing has ever promised him.

And for now, it is enough.