The first time the college football world was introduced to Tua Tagovailoa, he was coming off the bench during the second half of the 2018 national championship game in Atlanta. Out went a struggling Jalen Hurts, who had gone 26-2 as a starter and had once been named SEC Offensive Player of the Year, and in came this lefty from Hawaii, this true freshman no one had ever heard of, who showed no signs of being overwhelmed by the moment as he methodically led Alabama back against Georgia.

In the first possession of overtime, down three, he took a sack and still wasn't rattled. Instead, facing second-and-26, he dropped back and found DeVonta Smith racing down the sideline for the winning touchdown, and all hell broke loose. Tagovailoa and his teammates sprinted around the field that night in a state of joy, almost unsure of what to do with themselves after such an improbable, historic comeback. Even the usually reserved Nick Saban let himself get swept up in the moment, the coach smiling from ear to ear as he lifted his arms in celebration.

There was something about the way Alabama won that felt new and transformative. It was as if the DNA of a dynasty that had long thrived on defense and careful execution on offense had been recoded in a single night by a quarterback whose talents we were only beginning to understand.

Which is what made the scene on Saturday afternoon at Mississippi State so jarring. Alabama's 38-7 win was an afterthought. There was no celebration as many of those same teammates from the 2018 title game walked off the field at Davis Wade Stadium with their heads hung low, processing what they'd seen hours earlier. Tagovailoa, their star quarterback and leader, was gone after being taken by helicopter to St. Vincent's Medical Center in Birmingham. He was hurt late in the first half on a seemingly innocent play, dislocating his right hip, an injury that would end his season and almost certainly his historic career at Alabama.

Najee Harris, who had scored a career-high four touchdowns in the game, was borderline despondent. "I'm just hurt," he told reporters. Saban spoke about the injury in grave terms, even though a definitive diagnosis wasn't clear at the time. He called what happened a "freak thing." If he could do it over again, knowing how it would end, he said he would not have put Tagovailoa back in the game, with Alabama ahead by four touchdowns and halftime moments away. But Tagovailoa said he wanted one more series, and Saban said OK.

And now? Now Saban was using words no coach ever wants to use. "Godspeed to him and his entire family and our thoughts and prayers are with them," he said. "[I] hope this is not so serious it has any long-term effect on his future as a player."

If this is indeed the end of Tagovailoa's time at Alabama, if he opts to enter the NFL draft, it's a shame he went out on such unfortunate terms. Seeing him writhing in pain on the field, his face bloodied, unable to walk off under his own power, was the antithesis of the player we have seen perform near-superhuman acts for the past two-plus seasons.

You could feel something special building after that coming-out party in Atlanta. Tagovailoa beat out Hurts for the starting job and proved he deserved the hype. Coaches marveled at his presence in the pocket; one staffer said it was almost as if he had eyes in the back of his head. Defenders took stock of his poise and how his eyes scanned the field so quickly; they could only shake their heads when he fit passes into windows that didn't seem to exist. He was an artist, an enigma. Former Alabama offensive coordinator Lane Kiffin got flashbacks of recruiting him in high school. "It's just a magical aura and accuracy with the ball," he said.

Remember Tagovailoa's first touchdown pass as a starter in the season opener against Louisville? He was trapped by the defense, spun around wildly and, without breaking stride, flung the ball in the general direction of ... nobody? But then Jerry Jeudy appeared, six points went on the scoreboard and no one ever questioned him again.

The sport hadn't seen anything like Tagovailoa in an Alabama uniform before. He almost single-handedly changed the offense, dragging it into the 21st century with his ability to spread the ball all over the field. Instead of the I-formation, he threw to four and five receivers. Instead of grinding down the clock, Tagovailoa & Co. were lighting up the scoreboard in seconds.

His feel for the game was on another level. Texas A&M coach Jimbo Fisher said he was the kind of quarterback who could beat you with his "legs, feet [and] mind." Hall of Famer and ESPN analyst Steve Young recently pointed to Tagovailoa as an example of where intuition -- "the three-dimensional chess in your head" -- and physical ability collide. "Those rarely come together," he said.

If not for a sprained ankle he suffered during last season's SEC championship game, Tagovailoa might have won the Heisman Trophy instead of finishing as the runner-up to Oklahoma's Kyler Murray. But then -- just when you thought he was falling back to Earth -- he did something magical again: He had surgery and returned just four weeks later, throwing four touchdowns in an Orange Bowl win against the Sooners.

Whatever humbling he experienced against Clemson in the 44-16 title game loss weeks later didn't derail him. Tagovailoa came back this season more determined and more focused than ever. He suffered another high ankle sprain -- this time to his right ankle -- had the same surgery and returned in three weeks instead of four, tossing four more touchdowns in a shootout loss against LSU he might have won if there were five more minutes left to play. Saban called him a "warrior" for that performance, and in sports terms, who would argue otherwise? Before the hip injury against Mississippi State, Tagovailoa had thrown 31 touchdowns and only three interceptions all season.

If Tagovailoa's time in college is over, take a minute to marvel at his passing numbers to date: 7,442 yards, 87 touchdowns and 11 interceptions in essentially two full seasons as a starter. He's been responsible for more total touchdowns (96) than anyone else in school history, and he could hang it up right now with a legacy as one of the most entertaining, compelling, accomplished quarterbacks to play college football.

"He's one of the best competitors, one of the best young people in college football," Clemson coach Dabo Swinney said. "... He's the epitome of a winner."

And it's those same admirable qualities -- that warrior mentality, that drive to win at all costs -- that might have made Tagovailoa more vulnerable on the football field. He had an unflinching belief that he could make something out of nothing, and the numbers backed it up. He was so successful at extending plays and eluding the oncoming rush -- his 20 passing touchdowns under pressure are the most of any quarterback since 2018 -- that he had no reason to stop trying.

Such was the case after he sprained his ankle the first time as a sophomore. This season it happened all over again, when he tried to escape the Tennessee defense, to buy a little bit more time, and instead was yanked down to the turf, where his ankle moved in ways it wasn't supposed to. Then finally, on Saturday, he again refused to let the play die and paid the price. He rolled to his left and kept searching and searching for an open man until he knew he was caught; he threw the ball away just as two defenders fell on top of him, causing him to land awkwardly on his right leg. This time, Tagovailoa couldn't get up; he couldn't have doctors stitch him up and keep on going.

Monday, he had hip surgery in Houston. We won't know the full extent of his injury and path to recovery for some time.

For now, though, Alabama will have to move on without him, unsure of what the future holds. But it can do so knowing that whatever happens next, there's no doubting his impact on the program, which began in thrilling fashion and somehow kept delivering moments that took your breath away.