GREEN BAY – Every time Head Coach Mike McCarthy was asked about Geronimo Allison during training camp, two descriptive words were used, almost without fail.

Toughness and tenacity.

They aren't the only admirable traits for the Packers receiver who has climbed from undrafted rookie to No. 3 on the depth chart in less than three years, but they help illustrate how he has risen so dramatically in so short a time frame.

Soft-spoken and often smiling in the locker room off the field, Allison apparently is a different guy on it. He's a more physical player than his somewhat wiry 6-foot-3, 202-pound frame would suggest, and he's never shown any signs of being intimidated in the NFL despite a humble football path that included just one year of the sport in high school followed by two seasons at a junior college.

If tough and tenacious is what it has taken to achieve what he has, don't expect Allison to change.

"It comes from my journey to get to this point, and it also comes from my upbringing, where I come from," said Allison, who grew up in a less-than-glamorous part of Tampa, Fla. "I come from a rough urban community. Some people call it the projects, some people call it the hood. Everybody classifies it differently, but it is a rough community.

"That kind of shaped me but didn't make me. I don't have to walk around and have that stigma behind me because I'm not in that environment anymore, but that environment helped shape me to when I need to turn that switch on, I can turn it on."

As Allison enters 2018 as probably the one player on the Packers' offense assuming considerably more responsibility than he ever has before, good luck finding anyone in the locker room who doesn't believe he's up for the task.

He can't replace Jordy Nelson, but in sliding up to the No. 3 spot behind Davante Adams and Randall Cobb, Allison will play a big part in the Packers' attempt to continue humming along without him.

Allison has earned the trust of quarterback Aaron Rodgers little by little over his first two years. As a rookie in 2016, he came off the practice squad to catch a TD pass in his first NFL game in Atlanta. Later that season with Cobb sidelined due to injury, he came up big down the stretch, diving for a memorable, game-clinching touchdown catch at Detroit to conclude one of Rodgers' interminable scramble drills.

Even in the playoffs, he caught three passes in the big win at Dallas, all for first downs. Then last year in Week 3 against Cincinnati, he turned in his career game – six catches for 122 yards, including a 72-yard catch-and-run on third down in overtime to set up a game-winning field goal.

Asked what kind of 2018 season Allison could produce in his elevated role, Rodgers didn't make any grand pronouncements, but all the elements for a significant contribution are there. To Rodgers, Allison has put in the work. Now he just needs to get open.

"The ball goes to the open guy," Rodgers said. "G-mo, I've always had a lot of confidence in him. He's a great teammate, has a great professional work ethic, he's prepared, he knows the offense really well, and that's the starting point of any type of trust is the mental part.

"I expect him to be in the right spot, to run the routes the right way, and if he's open, he'll get the ball."

Allison's journey hasn't been without its stumbles. He was suspended for the opener last season for a substance-abuse violation, and his fumble late in the fourth quarter at Carolina in Week 15 ended the Packers' (and Rodgers') comeback and playoff hopes.

But he returned for the offseason program, after Nelson's departure, ready to seize the chance in front of him. He was so steady and reliable in training camp that none of the Packers' three rookie draft picks at receiver ever seriously challenged his place on the depth chart.

Allison has the confidence not only of Rodgers but his veteran receiving mates, too. The way he has performed in a pinch in the past has helped, but that's not all.

"In the meeting rooms, he's a pro. In the weight room, he's a pro," Cobb said. "That respect comes from many places other than the football field, and G-mo has done everything he can."

From a rough section of Tampa to Iowa Western Community College to the University of Illinois to Green Bay, Allison was a heck of a story even before he reached his current status on the Packers' offense.

Through it all, he has stayed focused on his faith, which has helped him avoid distraction when he does reflect on what he's accomplished, which would have been unthinkable just a handful of years ago.

"I think about it briefly at times. I try not to dwell on it," he said. "Most times when I think about it, I'm talking about it with my family, talking about it with my friends, the journey I come from, and I almost get emotional, because it's been a long road, and now I'm faced with a blessed opportunity."

He drew on his toughness and tenacity when the only high expectations were his own. Now that the external pressures have grown, Allison won't approach things any differently.

"I always took my game pretty serious. Always," he said. "It's just how I prepare, how I go about my business, how I contribute and how I've been raised.

"Coming from 12, the expectation is anybody that's in there is expected to play up to his caliber. That goes from the first receiver down to the eighth receiver. When you're active and you're out there, and you're out there with somebody who's great like 12, you're expected to make plays and help the team win."