GREEN BAY – When there was reason not to, the Packers stuck with undrafted rookie cornerback Tony Brown last year.

Their faith in him could end up paying huge dividends for Mike Pettine's defense in 2019.

With starter Kevin King currently sidelined with a hamstring injury, Brown joined Jaire Alexander and Tramon Williams as the corners with the No. 1 nickel defense in training camp this week and is slated to start the preseason opener Thursday night vs. Houston.

King's injury history through his first two-plus years in the NFL has been troublesome, so the opportunity afoot is significant for Brown. He could end up being a defender Pettine will be counting on as 2019 unfolds, and this next month is his chance to reinforce the team's belief in him.

"He competes and I feel comfortable with him when he's out there," General Manager Brian Gutekunst said. "He loves to play football and he hasn't really backed down from any challenges since he's been here."

That includes challenges of his own making, as Brown's tenure in Green Bay got off to a rocky start last year. The Packers signed him to their practice squad in Week 1 after he didn't make the Chargers' roster as a college free agent, elevated him to the active roster by the end of September, and thrust him into action on defense at Detroit in Week 5.

But after breaking up a third-down pass to the Lions' Kenny Golladay in the third quarter with the Packers on the comeback trail, Brown was flagged for taunting along the Detroit sideline.

The following week he committed another personal foul, for unnecessary roughness, on a San Francisco kickoff return, giving the 49ers prime field position late in the fourth quarter of a tie game.

At that point, it would have been easy as well as understandable for the Packers to cut their losses and move on. But they didn't, believing in the athleticism and talent Brown possessed as a top-ranked national recruit who played 51 games for Alabama and piled up a bunch of track honors for the Crimson Tide in the offseasons.

Asked this week about those untimely, aggravating penalties, Brown said he never really felt in danger of getting cut. The coaching staff took him at his word that the taunting wouldn't be an issue again, and he said the film showed the flag against the 49ers was thrown in error.

"With those situations, I was blessed enough to be able to be retained here, to stay here," Brown said. "Just learn from them."

From there, Brown recovered from a minor hip injury to post 30 tackles, four pass breakups and two forced fumbles over the second half of the season. He started three of the final four games and also finished the year with six coverage tackles on special teams.

Through a full offseason in Green Bay this spring, progress has been evident. Working for a second straight year in Pettine's system has been a huge plus, but he's also gained an edge mentally from his experience as a rookie.

The phrase "slowing the game down" is used a lot by young players. In Brown's case, he's accomplished that by reducing what he's thinking about and processing on any given snap, so he can react faster and put himself in better positions.

"If you ask any DB that's been in the league for a while, when you're younger, you try to cover all the routes in the route tree when you're out there," Brown said. "But guys are so skilled, it's impossible to cover somebody who's just as fast or maybe faster and quicker than you and to think you're going to cover the entire route tree.

"So as you get older, you've seen enough routes and releases, it allows you to break down a formation, to break down a guy, his stance, where's he's at on the field, and eliminate certain routes."

Fewer options for the receiver means fewer potential reactions needed by the corner. Brown put that mentality to use in the Packers' Family Night practice last week, jumping a third-down sideline route by Equanimeous St. Brown, picking off DeShone Kizer's pass, and taking it the other way for a pick-six and the defensive highlight of the workout.

"My first play I got in (during Family Night), they caught it on that play because I feel like I didn't trust my instincts," he said. "So like maybe five plays later, I got that same vibe."

Brown carried that over to a couple of solid joint practices against the Texans this past week. Using his aggressive, in-your-face style at the line of scrimmage, he broke up a couple of passes intended for No. 1 receiver DeAndre Hopkins, one of the league's best.

Brown still does his share of jawing on the field, prompting Aaron Rodgers to say he likes to complete a pass against Brown in practice just to shut him up. Brown enjoys the banter, but not at the expense of losing his focus, because he's aware of the road he's still on as an undrafted, unproven prospect.

"There's a revolving door in this league, 2,000 jobs, so I understand there's somebody out there that wants my job, there's somebody out there looking to replace (me) right now, regardless of how many plays I make or what I do in this league," he said. "So I know every day I have to prove to myself and beat out that person in my mind, whoever that person is. Yeah, every (instant) I'm trying to prove it to myself that I'm good enough to be in this league, that I am supposed to be here."

All he has to do is look three lockers down for Exhibit A of what can be, and what it looks like when it's done right. Williams, undrafted back in 2006, is still going strong at age 36, and a guy Brown watches and listens to intently.

No one is saying Tony Brown is the next Tramon Williams. Even an uber-confident, brash talker like Brown knows any such comparison is drastically premature. In that respect, he hasn't earned anything yet.

But the perfect role model is right there, and Brown already has a couple of rookie lessons under his belt no one can teach.

"He's like an inspiration to me, man. I look at Tramon, he's the goal for me," Brown said. "He maintains great health, physical fitness. He's so knowledgeable of the game, he has great character.

"He's a guy I like to try to be around as much as possible, just to check him out for as long as he's here, to try to grab as much as I can from him so I can apply it to my game and be in the league as long as he has."