IRVINE – From a purely skill-set perspective, Sam Shields always believed he’d eventually find his way back to the NFL, and make good on the chance a team offered him to play in its defensive backfield.

That his painful and poignant journey has taken him to Los Angeles to add depth and talent and the potential of another ball-hawking cornerback to a loaded Rams secondary seems most appropriate. On a talented team that’s rising to must-watch status while bursting at the seams with stars such as Todd Gurley and Jared Goff and Marcus Peters and Aqib Talib and Ndamukong Suh and, eventually, Aaron Donald, Shields adds the element of a Hollywood ending, should he successfully seize the opportunity the Rams have afforded him.

Movie scripts usually follow a three-act structure. The setup. The confrontation. The resolution. For better and worse, Shields has experienced Acts I and II.

That he’s now navigating his way through the final act is both humbling and exhilarating. And in some ways, surprising. But mostly it’s being embraced with appreciation.

“I’m blessed,” Shields said on Sunday after practicing for the first time in full pads since 2016.

But more on that in a bit.

For all that the brutal physicality of football has taken from the 30-year-old Shields – the result of four concussions across six seasons with the Green Bay Packers, including the one on the opening weekend of 2016 that knocked him out of the game he so desperately loves for more than a year-and-a-half – it never laid a finger on the kind of world-class athletic skills necessary to register 18 career interceptions and a berth onto a Pro Bowl team.

Even as the days and weeks and months passed without a reprieve from the lingering effects of the concussions, the piercing headaches that caused so many restless nights only to throb even more painfully during the day, and the constant feeling that something just wasn’t right, he never, ever doubted that he’d still be able to perform at an NFL level if he could just somehow, some way, finally outrun the frustrating symptoms he was dealing with.

“I still have my speed,” Shields said with a sly smile.

Oh, yes. That speed. He clocked 4.3 in his 40 at his pro day back in the day at the University of Miami. And even though it didn’t land him in the 2010 draft after making the late switch from wide receiver to cornerback, it didn’t take long for him to prove himself as a lock-down cornerback and an undrafted star for the Packers.

As long as he had that speed, he knew he’d have a chance to regain his spot in the NFL.

That conviction pulled him through the grueling first part of 2017, when constant headaches tortured him to the point that he checked himself into UCLA’s esteemed neurology department seeking relief and peace of mind.

It inspired and pushed him as his condition slowly but surely improved while being treated at UCLA. Every new day offered more hope and comfort than the one preceding it. And while he still knew he had a ways to go, the road back to recovery was becoming clearer and clearer by the day.

And then, out of the blue, it happened.

With literally no forewarning or doctor’s prediction, Shields woke up one morning after the conclusion of the 2017 season and felt, well, entirely like himself again. It was subtle but powerful. No headache. No disorientation, No dizziness. Just, like, normal.

“I just felt better out of nowhere. It was crazy,” Shields said.

He immediately knew what to do next. “I just said: Let’s go work out.”

And so he did. Nothing crazy, mind you. But as any proud athlete would, he pushed himself. If the sudden reprieve was a mirage, he wanted to find out sooner rather than later.

Upon rising the next day, he took stock of himself. A smile soon emerged.

“I felt fine that morning,” he said.

Another hurdle cleared.

One day of working out became two, Then three and four and five. He got through every one of them perfectly fine. He rose the following mornings feeling great.

“That’s when I finally realized I was all right,” he said.

It goes without saying that peace of mind and good health is priceless. And after struggling to find both for so long, Shields wasn’t about to take either for granted.

But he’s also an athlete. A proud one. It doesn’t define him, necessarily, but to deny the significant part it plays in who he is would be arguing the earth is round.

The athlete in him, the football player and competitor, was intent on writing the final act of his career, rather than letting an injury have final edit rights.

The Rams had been interested in Shields almost from the moment the Packers released him in February 2017, but understanding his need to get right physically and mentally, they gave him the necessary time to put enough distance between himself and the concussions.

Upon finally getting medical clearance to resume his football career – including spending two days with the Rams undergoing a battery of tests and on-field workouts – he signed with the them last March on a one-year deal that puts him in a talented secondary alongside Peters and Talib and Troy Hill and Nickell Robey-Coleman and LaMarcus Joyner and John Johnson III.

Less than a week into camp, Shields is already flashing the skill set that made him one of the premier corners in the game. That he adds that element while playing in a reserve role is a benefit the Rams don’t take lightly.

“He’s doing a great job,” said Rams coach Sean McVay. “He’s one of those guys you talk about a lot of the big-time guys that we’ve signed, but I think people forget what a productive player Sam’s been in this league. Elite man-to-man skills, unbelievable lateral agility and just short space quickness.”

Given his history with concussions – and the alarming recent data about NFL head injuries and their long-range ramifications – it would have been natural for Shields to have reservations. But he returns with a clear conscience after consulting with doctors. The decision, ultimately, was his to make alone. His family offered only support.

“It was all on me. I felt great,” Shields said. “I had a year and a half to think about it. To be with my family. So I definitely had time to think about it and I definitely feel I made the right choice.”

The challenge now is shaking off the rust of not playing football for nearly two years. He cleared a big hurdle Sunday practicing for the first time in pads.

“It was different. Just the pads of it. Just the (fatigue),” he said. “It was a lot, for the first time. But it felt good, to be back in it. Just, where I’ve come from, just mentally that’s the big part and I’m definitely working on that. It was a start. I can say that.”

Eventually, he’ll have to take the field against an actual opponent in which all restrictions relative to contact will be lifted. Shields knows the day is looming, and he’s bracing for it. But he won’t approach it with trepidation or fear. Under no circumstances will he adjust his style of play. He won’t. Can’t. The first time he lines back up in a real game, he’ll bring it just as he always does.

“You have to,” he said. “You have to be mentally strong. You have those thoughts and you’ll be behind. It’s no way I can have those thoughts. I just have to keep pushing.”