KNOXVILLE, Tenn. -- Ashley Smith's cell phone was buzzing at 2 o'clock in the morning last New Year's Day.

She didn't even bother to look at the caller ID. She already knew who was on the other end. It was her baby brother, Trey Smith, known more commonly around the football world as one of the most imposing interior offensive linemen in the college game. Smith was driving back to Knoxville from the family home in Jackson, Tennessee, and had some news to share with his sister.

"I usually get nervous when the phone rings at crazy times, but Trey had already told me he was going to head back to campus that night on New Year's Eve and wanted to talk," Ashley recalled. "I remember the conversation like it was yesterday."

She also remembers the conviction in her brother's voice, the same conviction that has helped shape one of the best comeback stories in college football this season -- for Smith and the entire Tennessee team.

"He just told me that he was at a peace with everything, and while so many people out there were telling him that he needed to walk away from football and hang it up, he was being led by the Lord to stick with it and that he was going to play again," Ashley recounted. "And not just play, but excel."

True to his word, Smith never flinched. But, then, when has he? He lost his mother, Dorsetta, to congestive heart failure when he was still in high school. He was diagnosed with blood clots in his lungs following a freshman season at Tennessee in 2017 that saw him earn Freshman All-American honors. And after being cleared by doctors just prior to the start of the 2018 season, Smith was pulled off the field for the final five games when tests appeared to show that the blood clots had returned.

"I know it looked bleak to a lot of people, and I know everyone kept saying I wouldn't play again," Smith told ESPN. "But, in my mind, I was going to play again. Some were [concerned] about me playing again, and some doubted me. I'm cool with that. I was going to prove them wrong and am going to keep proving them wrong.

"Once again, it goes back to having faith, and I never lost that faith."

Tennessee head coach Jeremy Pruitt sat down with the junior left guard about this time a year ago just to remind him that the most important thing was making sure he was healthy. And if that meant stepping away from football for good, so be it.

"There's a lot more to life than just football, and I wanted to make sure that Trey understood that his health, his long-term health, was what was most important to me," Pruitt said.

But after further consultation with multiple specialists who reviewed Smith's case, doctors determined the tests performed in October 2018 were suboptimal and more consistent with potential scar tissue from Smith's prior blood clots in February 2018 and not recurrent blood clots.

Smith, along with his family and UT's medical staff, met again to review the risks. After consulting with Dr. Stephan Moll at the University of North Carolina, Tennessee's head team physician, Dr. Chris Klenck, said a regimen was developed to allow Smith to participate throughout this season while keeping his risk of new blood clots to a minimum. It was still a long road back for Smith, who admits he had to lose nearly 40 pounds after sitting out those final five games a year ago. But he continued to grind. He lived in the weight room and got in extra cardio every chance he had. He also started eating healthier, stopping late-night runs to Cook Out for burgers and fries, and instead becoming a salmon aficionado. A physical specimen from the day he stepped foot on campus, Smith got even stronger. One day last summer, the Tennessee strength coaches had to stop him at 375 pounds on the power clean, an Olympic weightlifting exercise.

ESPN analyst Cole Cubelic said the 6-foot-5, 335-pound Smith, who cannot fully practice, was one of the top three or four offensive linemen in college football during the second half of this season. Bryan Lynn/Icon Sportswire

"When your power clean gets better, that means you're more explosive in your body," Smith said. "I was going for 395 and thought I could get it. I really wanted 405, but they didn't want to chance it."

The trickiest part of the doctors' regimen for Smith was he had to avoid contact in practice, which makes it exceedingly difficult to prepare for the rigors of a game, particularly for a lineman. Smith said he probably has had only two full-contact practices going back to preseason camp. The rest have mostly been walk-throughs.

"It's incredible to see everything he's come back from," said Tennessee quarterback Jarrett Guarantano, one of Smith's closest friends on the team. "He has barely practiced during the season, and then on game day, he comes out there and is one of the best offensive linemen in the country. It's been inspiring for all of us."

So, as Smith walks onto the gridiron Thursday night against Indiana in the TaxSlayer Gator Bowl (7 p.m. ET, ESPN and ESPN App) in what could be his final game in a Tennessee uniform, he will do so with the satisfaction that he didn't just return to football, but he also came back as one of the most dominant players in the country at his position. Smith showcased the same form that made him ESPN's No. 1 overall prospect when he signed with the Vols in 2017, earning him a consensus first-team All-SEC selection and garnering some All-America mention.

"Every time I stepped onto the field, I wanted to be the most physical force out there," said Smith, who became a YouTube sensation this season with some of his menacing blocks. "But I still need to be more consistent."

Smith is a fan favorite at Tennessee and an active member of the community, organizing food drives and collecting coats for those in need. Bryan Lynn/USA TODAY Sports

Off the field, he was active in the Knoxville community, from organizing food drives for the homeless to collecting coats for those in need when the weather turns cold. For that work, he was one of three finalists for the Jason Witten Collegiate Man of the Year Award.

The best part of this season for Smith, though, was seeing the way Tennessee's team rebounded from a brutal start, winning six of its last seven games after opening the season with back-to-back home losses against Georgia State and BYU. The veterans on the team were a huge part of the turnaround, and Guarantano said Smith was one of the catalysts.

"We never gave up on each other, and Trey was a big part of that," Guarantano said. "As a team, it took us a while to click and understand everything. But when it did, you see what happened. Trey was the same way and really the heart of the team, because when it clicked for him, he was unstoppable."

ESPN analyst Cole Cubelic, a former offensive lineman at Auburn who studies offensive line play, said the 6-foot-5, 335-pound Smith was one of the top three or four offensive linemen in the country during the second half of this season.

"Considering how little practice he had makes it one of the more impressive offensive line seasons I've seen in a long time," Cubelic said. "His power and willingness to finish blocks separates him from almost everyone else in the nation."

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Smith has yet to finalize his decision on whether he will declare for the NFL draft. He has gathered some information from NFL clubs, but has been adamant about not wanting to discuss his future in any detail. He is scheduled to graduate in May with a degree in sports management and a minor in business.

"My focus is on this university as long as I'm here, and once I finish this last game, I'll sit down and think about what I want to do," Smith said. "Right now, my focus is on beating Indiana."

He never considered sitting out the bowl game, a trend becoming more common among top players, especially those players with any injury or health issues.

"I don't even know why it would cross my mind, to be honest," Smith said. "I don't blame guys who don't play and never understood knocking guys for not playing. Everybody's situation is different. But for me, I've still got a lot to prove, and I want to play in every game I can in that orange and white."

Before Smith's mother ever got sick, he promised her that he would one day make it to the NFL. He said not a day goes by that he doesn't think about her.

"There were a lot of moments this year I wish she could see," Smith said before pausing and breaking out into a soft chuckle. "But being quite frank, if she were still here, I probably wouldn't be playing because she wouldn't want me to play."

Ashley Smith said her mom is undoubtedly "smiling down from heaven on her baby boy," and not just because he has been devouring opposing defensive linemen on the football field.

"This is just the tip of the iceberg of what God has in store for Trey, both on and off the field; and everything Trey does, he gives God the glory," she said. "That's what our mother would be most proud of."