In 2012, after a four-year career at Notre Dame that wound up being a little short on highlights, running back Jonas Gray found himself drawing the attention of the NFL. Gray wasn't sure where he'd land in that year's NFL Draft, but expectations were somewhere between the second and fourth rounds, dictated ultimately by how he ran during the pre-draft process at venues like the NFL's rookie scouting combine and Notre Dame's Pro Day.

Unfortunately, there would be no 40s, no simulated routes out into the flat in shorts and a T-shirt for Gray.

A torn ACL in November of his senior season derailed the Michigan-born Gray's professional hopes for a time.

But it wouldn't last.

Gray underwent surgery in December, and thanks to some shrewd maneuvering by his agent, landed with the Miami Dolphins as a priority free agent with something close to, but not quite, a guarantee that he'd be on the roster for the entire season, no matter what.

"I was looking for an opportunity," Gray tells Headlines and Global News. "That's all I needed, to be on somebody's roster, to have a chance to be a part of any NFL organization."

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The NFL is a much different place these days for running backs. What was once a highly coveted position is simply no longer valued in the same way by the league's legion of scouts and personnel men. Sure, two backs - Todd Gurley and Melvin Gordon - went in last year's first round, but it was the first time since 2012, Gray's draft year, that a ballcarrier went that early. It's a position where general managers believe value is to be found in later rounds and the free agent market.

It's a boon to players like Gray, who bring plenty of potential if little in the way of special physical talents or a pedigree of college production with them to the league. But it's also why carving out a niche and building a career that lasts beyond a season or two is so tricky.

With a berth in Miami post the 2012 NFL Draft secured, Gray turned his attention to healing, but also learning, to focusing on personal and professional growth. It's a focus and a mindset that Gray would continue to pursue and hone throughout his now four-year NFL career - in length, if not in active roster status.

"My whole mindset that first year for me was to just absorb as much knowledge as I can and learn from NFL guys and get back into the best shape that I can," Gray says.

In beautifully cyclical fashion, ask Gray, now on his fourth NFL franchise, the Jacksonville Jaguars, how he approaches his role as a 25-year-old backup with aspirations for more, and he'll parrot a similar line.

Only now he's that "NFL guy" passing along the how tos to the likes of T.J. Yeldon and Denard Robinson.

"To do all that I can to help the team win and really make a mark where guys can say, 'we won because of you,'" Gray says of what he's hoping for in 2016, his second season in Jacksonville. "Team victories."

His time in Miami the first go-round - he'd wind up there again in 2015, yet another leg, albeit a short one, on that chaotic journey they call professional football - didn't result in playing time, but it was a start.

That's all Gray needed, all any NFL hopeful really wants. And when the next year rolled around, when he finally had a chance to hit the field in preseason, that's when it clicked.

"I knew that I belonged in the NFL. No doubt in my mind," Gray says, his voice resolute. "The fact that I had made it that far dealing with all the things I had to deal with - the knee injury and going undrafted - to still be in the league, I knew that I belonged."

It didn't get Gray a roster spot, that strong preseason performance, but life as an undrafted NFL player rarely works that way. Having the talent is only one part of the equation - learning, growing, discovering your role, is the other, perhaps larger piece.

Gray joined the Baltimore Ravens, continued his quest for a football home while operating against the vaunted Ravens defense in practice, yet another opportunity he took to learn, before signing a future/reserve contract with Bill Belichick's New England Patriots in January 2014.

It would be the most educational experience of Gray's career.

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"I'm happy about it," Gray says. "I had the opportunity to grow, learn a lot, experience a lot, be around a lot of good players. A Hall of Fame coach and a Hall of Fame quarterback, and obviously I won a Super Bowl so, no regrets at all, no frustration."

Gray's signing in New England didn't come with fanfare. He didn't make the team out of camp in 2014, landed initially on the practice squad. But an October call-up to the active roster would provide Gray a glimpse of what life as a starting NFL running back, with all the glitz, glamor and accolades, was like.

On Nov. 16, 2014, Gray rushed for 201 yards and an astounding four touchdowns as he and the Tom Brady-led Pats steamrolled over the AFC rival Indianapolis Colts.

Gray was suddenly a star. Who was this Jonas Gray and where did Belichick, notorious for plucking players off the NFL scrap heap and turning them into bona fide contributors, find this one?

It wouldn't last.

Gray was late for a team meeting in November and Belichick, also notorious for his no-nonsense attitude, oftentimes to a fault, relegated the talented ballcarrier to the bench. He was forced to watch from the sidelines as Brady led the Pats to their fourth Super Bowl victory of the Belichick era.

Gray was cut by the team the following September.

Despite his brush with a leading role, with fame, despite leading the Patriots in rushing during the preseason, Gray says there are no regrets. Though he admits there is a "what could have been" that lingers in the back of his mind.

"I take it all as a learning experience and it's made me a better player," he says.

Gray was back to NFL square one, landing initially with the Dolphins for a second time before the Jaguars signed him to their active roster. Looking back, Gray feels good about first season in Jacksonville. Again, Gray learned and grew. But this time, with four NFL franchises and two NFL seasons under his belt, Gray wasn't coming in as the unheralded youngster. He's more the cagey vet now, carving out a role not just with his exploits on the field but his willingness to be a team-first player off of it as well.

"The thing that's crazy is people don't really understand how hard it is to go into an NFL locker room as a new player, whether you've been in the league, whether you've had success in the league, whatever the case may be, it's hard to go in and be asked to play," says Gray.

Learning the playbook, connecting with teammates, performing at a high level from the get-go, almost as if the human side of you didn't exist - it's what NFL free agents have to do. If you're lucky, you land somewhere and stick. If you're not, if your journey is not yet complete, you better learn to get that verbiage and those plays down quick.

Part of the reason Gray can't feel too much ill will toward Belichick and company is that he believes his ability to ingest a playbook, to ingratiate himself to a team and an offense, is a direct result of the skills he learned in New England.

"My whole thing was, being in a situation where I had to learn the playbook fast, and I had to think on my toes and really study and learn a lot of concepts, I think my time in New England really helped me in that situation," Gray says. "I went into Jacksonville and the last three games, and I really did, whatever the gameplan was, week-to-week knew it as well as the quarterbacks did."

Gray finished 2015 with just 45 rushes for 176 yards, with 14 of those carries and 54 of those yards coming with Jacksonville. To Gray, it's a start. A "springboard" that will hopefully propel him to greater heights next season.

For most NFL players, it'd be pretty eye-opening to be a part of the type of offensive output the Jaguars, led by quarterback Blake Bortles, managed last year. Bortles threw for 4,428 yards and 35 touchdowns, and wide receivers Allen Robinson and Allen Hurns combined for 24 touchdowns.

But for Gray, for the seasoned vet in the increasingly young Jaguars' locker room, it was the second time in his professional career he's been privy to such a sight. His job then became fitting in.

"I've been a part of a similar offense that's flying well on all cylinders and doing well and scoring a lot of points, so my job for me was to come in, protect the quarterback, have a positive run if I can and just impact the team in a positive way," he says. "So I said every time I go out there, if I have to be the toughest guy on the field this play, I was doing whatever the team or whatever the offense needed me to do to help keep the success going."

And therein lay the truth of Gray's success, his path to a continued NFL existence.

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At this point in his career, Gray doesn't worry about gameplans. He doesn't worry about where the ball is likely headed once Sunday rolls around, what matchups the Jaguars coaches think are ripe for exploitation. He knows his role, and he relishes it, game to game and, if he can make it work, year to year.

"I like to try and exert my toughness and will on the opponent in pass protection," Gray says, gritting his teeth as if preparing to absorb the blow of an attacking defender. "And they know that I'm that all-around running back. The defenders know that."

For NFL running backs, there may be no greater proving ground than pass blocking. It's not glamorous. In fact, it's downright dangerous. Massive, downhill linebackers, safeties on a delayed blitz, corners with blood on their tongues and visions of grandeur in their eyes - a running back must be fearless, he must be selfless, he must be ready and willing when these players come marauding into the backfield.

You want to know how to make it in the NFL as an unheralded running back? Sure, there may be dazzling displays of nimbleness, of eye-popping, jaw-dropping athleticism, glory to be covered in and numbers to be racked up, but at the end of the day your worth to your team and your franchise is measured not just in yards and touchdowns, but in the sacrifices you're willing to make to keep the machine rolling, to keep yourself on the field.