INGLEWOOD, Calif. — He showed up in the spring as a man on the verge of being supplanted, a dead-QB-walking whose young replacement was a mini-slump or an ill-timed injury away from getting the keys to one of football’s most envied offensive schemes.

On Sunday night, Jimmy Garoppolo walked out of SoFi Stadium as the San Francisco 49ers’ quarterback, likely for the final time, with his head held high. He had battled through doubt and insecurity, the stress of four nerve-wracking elimination games and, for the past five-and-a-half weeks, a torn ligament in his throwing thumb that by all rights should have put him on the sidelines.

Having come so close to defying long odds and legions of skeptics by helping San Francisco reach a second Super Bowl appearance in three seasons, Garoppolo had nothing left to give — including, in this case, the plural version of one of the English language’s most powerful swear words.

“Now I can say the truth,” Garoppolo told Bally Sports. “Every play, I feel it. But we made it through.”

Ninety-one minutes after a sudden and wrenching 20-17 defeat to the rival Los Angeles Rams in the NFC championship game, Garoppolo stood in SoFi’s southeast tunnel, near the spread of to-go food outside the Niners’ team buses, and let it all out. He finally confronted the end of his time with the 49ers and told the truth about his injuries — physical and emotional.

“I can’t believe this s--- held up, to be completely honest with you,” Garoppolo said, gesturing toward his tender thumb. “The thumb, the shoulder … all of it. It was one thing after another. … Every time I threw. It was a lot.”

The last throw of Garoppolo’s day — and, almost certainly, his five-year run with the Niners — had been a desperation pass that bounced off the hands of running back JaMycal Hasty and into the arms of Rams linebacker Travin Howard with 1:09 remaining. Trailing by 10 entering the fourth quarter, L.A. and quarterback Matthew Stafford had seized the moment, scoring 13 consecutive points to secure the franchise’s second Super Bowl trip of the Sean McVay era.

Blue, white and yellow confetti lined the field that will host the Rams’ Super Bowl LVI showdown with the AFC champion Cincinnati Bengals on Feb. 13, at which point the 49ers and coach Kyle Shanahan will likely be plotting a future centered around Trey Lance, the No. 3 overall pick in the 2021 draft.

Garoppolo? He’ll probably be playing quarterback for another team, in another city — something that became apparent last March, when the Niners traded three first-round picks to move up nine spots in the draft, positioning themselves to select his replacement.

Facing that eventuality — and so much more adversity along the way — Garoppolo did something highly unusual. He elevated his game and dug deeper, and he impressed just about everyone in his orbit in the process.

“He played through so much s--- and all the s--- in his head,” said 49ers offensive coordinator Mike McDaniel, who has a legitimate shot at becoming the Miami Dolphins’ next head coach in the coming days. “Most of the time, when you draft somebody high, people fold. He got better, and that started in the offseason. Everyone noticed. It was really cool.”

Heading into training camp, Shanahan insisted Garoppolo was still his starter, but the quarterback knew the deal. Lance’s first week of camp was so impressive, especially from a mental standpoint, that many Niners coaches believed the rookie might be The Man immediately. Then Lance leveled off, and Garoppolo got to keep his job.

“Yeah, I think the competition, or whatever it is, it pushes you,” Garoppolo said. “When (the trade) happened, I think it kind of just sent me to a different zone. And I think that paid off this year. It paid off for this team. And good things came from it.”

Well — not right away. In early November, a desultory home defeat to the Arizona Cardinals dropped San Francisco into last place in the NFC West with a 3-5 record. At that point, it seemed that the switch to Lance was imminent.

“I think when we were back at 3-5 and everyone said that we should fire Kyle Shanahan and bench Jimmy G, and trade me, get rid of Fred (Warner, the team’s All-Pro linebacker). … Yeah, that was rough,” star tight end George Kittle reflected as he stood in SoFi’s north end zone long after the game. “Hey, this is a team that thrived on adversity. I’ve never been part of a team that’s gone through so much before. It was a very, very fun team to be part of. And we all believe in Jimmy.”

That was never more clear than when, in the final game of the regular season, the 49ers — who had to win to reach the playoffs — fell into a 17-0 hole against the Rams at SoFi and leveled the game in the fourth quarter before giving up a go-ahead touchdown with 2:29 remaining. Garoppolo coolly engineered a dramatic, game-tying touchdown drive and took the Niners down the field again to set up Robbie Gould’s walk-off field goal in overtime — San Francisco’s sixth consecutive victory over its rivals. That he’d done it after having suffered the thumb injury in a 20-17 defeat to the Tennessee Titans on Dec. 23 made the effort even more epic.

Three weeks later, after road playoff upsets over the third-seeded Dallas Cowboys (during which Garoppolo sprained his throwing shoulder, but played through the additional pain) and top-seeded Green Bay Packers, the embattled quarterback and the Niners showed up at SoFi again — as did tens of thousands of red-clad zealots who seemed to make up at least half of the 73,202 in attendance — hell-bent on completing another unlikely act of defiance.

For a long time Sunday, it looked like he, and they, might pull it off. Garoppolo (16 for 30, 232 yards) threw touchdown passes to Deebo Samuel (44 yards) and Kittle (16 yards), and the Niners led by 10 entering the fourth quarter.

“And we should have been able to close it out,” a devastated Shanahan said shortly before leaving the stadium.

The 49ers had their chances. Up 17-14 with 11 minutes remaining, they had a second-and-1 at the Rams’ 44-yard-line, but runs by halfback Elijah Mitchell and fullback Kyle Juszczyk (with All-Pro left tackle Trent Williams in motion, reprising a formation that had great success against the Packers) lost a combined one yard.

Shanahan elected to punt, a move that would have looked great had safety Jaquiski Tartt not dropped what looked like an easy interception on L.A.’s first play from scrimmage, with Stafford’s long pass to Van Jefferson instead falling incomplete. Given a reprieve, the Rams rallied to tie the game on that drive, forced another punt and marched down for the go-ahead field goal with 1:46 remaining.

Once again, for Garoppolo and the Niners, the season was on the line — with zero margin for error. After a touchback put the ball at the San Francisco 25, the quarterback and his teammates took the field thoroughly convinced they’d tie or win the game in regulation.

“Honestly, the biggest thing he brings to the table is he’s the calm in the storm,” Kittle said of Garoppolo. “Every time you get into a huddle with him, you always believe that you can go score. And I think that’s such a hell of an attribute, because not everybody has that.

“Sometimes you get in huddles and you don’t really know. It’s nothing against quarterbacks I’ve ever played with, but there’s just a difference. You can just feel that energy from him. And he’s just so confident in us, and his ability. We all believe in him. When he looks at you, you (think), ‘I believe in myself, but he believes in me too.’ And it makes me work a little bit harder.”

The 49ers ran three plays, and none of them worked. A Greg Gaines deflection forced a first-down incompletion, and on second down, Garoppolo, under pressure, threw short to Jauan Jennings, who was nailed for a 2-yard loss. Then came the interception while struggling to avoid a sack, and the abrupt end to an improbable run.

To many of those who weren’t part of that run, the interception confirmed their view of Garoppolo as a substandard player who isn’t good enough to win the big one. This quarterback, reviled on social media but beloved in the locker room, is used to that.

“It’s all part of the game,” he said. “I get it. If people are hating on you, you’re probably doing something right. That’s something I always keep in the back of my head.”

Amazingly, up until that moment, Garoppolo had managed to keep the thoughts about his tenuous job status, and Lance’s inevitable ascent, out of his mind altogether. An hour and a half after a heartbreaking defeat, the finality of the situation began to sink in. Certainly, he was disappointed and exhausted, but Garoppolo wasn’t awash in self-pity.

No, he hadn’t been perfect — as his critics are fond of informing the masses at virtually every opportunity — but he’d done something big and rare and commendable when logic suggested he couldn’t.

Yes, Garoppolo finally admitted, he was proud of what he and his teammates had accomplished.

Also, he was hungry.

“I’m starving,” he said, laughing, before loading up his plate with food to devour on the bus ride to the airport. As he said goodbye, completing his final interview of a long and surreal season, Garoppolo looked ahead to an uncertain future and tried to cling to his last moments as the highly admired leader of a resilient, defiant team.

“All through this, I haven’t even thought about (my future),” he said. “It’ll hit me on this plane ride, and probably tomorrow a little bit. But we’ll figure that out when we figure it out.”

He gestured toward the rest of his teammates, most of who were waiting on the bus, and politely excused himself.

“I want to enjoy this time, with these guys,” Jimmy G. said softly. “For as long as I can.”