MOBILE, Ala. — Levi Wallace was sitting in his dorm room at Alabama, half a world away from Tucson High, when a fellow student’s mom found out he planned to walk on to the Crimson Tide football team.

“She said, ‘You’re a little too skinny to play SEC football,’” Wallace said this week. “I never forgot that, all the way to today.”

The words motivated him on the weekends when he lifted weights by himself as a freshman in fall 2013, and then the following January, when he walked on to play for coach Nick Saban. He’d attended the school on the GI Bill and did not enter a game in 2015, but was eventually given a football scholarship in 2016.

The cornerback logged 11 career tackles before a breakout senior year. Wallace announced his presence to the football world in the 2017 season-opener, intercepting a pass in the third quarter when the No. 1 Crimson Tide beat No. 3 Florida State. He started in the national championship game, in which Alabama beat Georgia, despite suffering from the flu all week.

Wallace earned a trip to Saturday’s Senior Bowl, alongside the best — albeit more heralded — players in the country.

“Everybody told me I couldn’t,” he said. “There was motivation. I persisted in it. I listen to the same words, I replay them in my head. Some of those people are my biggest fans. I like that. I enjoy it.”

NFL teams do, too.

Wallace spent Senior Bowl interviews telling them how he didn’t receive much interest beyond Division II when he graduated from Tucson High; about how he decided to attend Alabama because his father, Walter Lee Wallace Jr., was a Crimson Tide fan and could offer financial aid after 21 years in the Air Force; and how his dad died of Amyotrophic Lateral Sclerosis (ALS) on the eve of his first college spring game.

“When they ask, I tell them — I had no offers coming out of high school,” he said. “They love it. A lot of teams say I had a lot of guts to walk on, particularly at one of the top programs in the nation. I’m proud of what I’ve done, what I’ve accomplished. I’m just looking forward to the NFL.”

His dream seems closer than ever. Wallace weighed in at the Senior Bowl at 6 feet, 176 pounds — about nine pounds heavier than he was during the title game, after he was ravaged by the flu. He’s on a 4,000-calorie-per-day diet, and hopes to play at 185 pounds or so in the NFL.

Matching up against some of the nation’s best receivers this week was nothing new: Wallace guarded Calvin Ridley, a junior who figures to be the first wideout drafted, during Alabama’s practices.

“Calvin’s probably the best receiver in the nation,” he said. “He’s got a skillset that’s unmatched, I think. Going against all the receivers this season that I played, I think Calvin stands alone.”

While Alabama players have been scrutinized by draftniks over the years — “We always play in big games, we have long seasons and we’re always on TV,” Wallace said — there’s no question their defensive backs receive special training. Saban, a defensive backs coach at heart, runs a pro-style defense that might be the closest approximation to the complexities of professional schemes.

“(Scouts) are kinda surprised about what we run at Alabama, because there are so many variations, variables and adjustments,” he said. “They’re definitely surprised at the knowledge we bring to the table.”

While no challenge can be worse than his father’s death, Wallace relies on lessons he learned at Tucson High. The Badgers went 2-8 in 2010, Wallace’s sophomore year, and coach Vincent Smith left the team. New coach Justin Argraves won seven games in each of his first two seasons. Along the way, Wallace was moved from safety to cornerback.

“Just being able to deal with adversity like that,” he said. “The coaches saw something in me, moved me to corner, and now I’m a corner at the University of Alabama and hopefully going to the NFL,

“So it started back at Tucson High, and I’m glad they did it.”

He was never more happy than in the moments after Alabama’s title-winning 26-23 overtime win against Georgia earlier this month, in which he had three tackles and a pass breakup.

“Right after the game I kinda thought, ‘This season is unreal,’” he said. “I love Alabama. I love the season we just had. To go out like that and come from a walk-on and win the national championship and start in the game was a dream come true. I’m glad I got to experience it.”

Former Star reporter Patrick Finley covers the Chicago Bears for the Chicago Sun-Times. He can be reached at patfinley@gmail.com