In 2012, Tim Hightower’s first season out of the NFL, teams regularly contacted his agent to inquire about his services.
“That first season,” Hightower said, “teams were reaching out every week.”
In 2013, when the 49ers running back was still sidelined, the calls came less frequently.
“Every other week,” Hightower said.
And by 2014, when Hightower still wasn’t fully recovered from the knee injury he sustained in 2011, the calls nearly stopped.
“It was once? Twice?” Hightower said. “And you just feel those opportunities getting further, and further, and further away. And you don’t know if you’re going to get another opportunity.”
The opportunity finally came in 2015. And Hightower, 31, took advantage of it after going more than four years — 1,484 days to be precise — between regular-season carries after he sustained a torn ACL with Washington on Oct. 23, 2011.
Before signing with the 49ers in April, Hightower, who ranks 19th among active running backs in rushing touchdowns (32), enjoyed a two-season career renaissance with the Saints. As the backup to Mark Ingram, he rushed for 923 yards, averaged 4.0 yards a carry and added 34 receptions while posting two 100-yard games.
With the 49ers, he’s expected to assume a backup role behind Carlos Hyde and fight for carries with a group that includes rookie fourth-round pick Joe Williams.
However, Hightower has far loftier goals. And he explained his mind-set when posed this question: Did he ever experience an I-did-it emotional moment after he finally returned to the NFL in 2015?
“Not yet,” Hightower said. “Don’t get me wrong, I’m thankful. I definitely realize the opportunity I’ve been given and I’m very thankful. But my goal wasn’t just to make it back. I’ve got a lot more to accomplish … The mark I leave I don’t want it to be, ‘Well, he did good for someone who had been off.’”
“I want to leave a mark where anyone comes back and says ‘Injuries happen in this game, but I can come back stronger.’ My goal is to help change the expectations of guys coming off injuries; of the expectations of running backs late in their careers.”
Hightower says his arduous four-year absence created a resolve and he now wants to end his career “stronger than when he started.” And that would be an accomplishment given the promising start to his unique career.
Hightower went to the Super Bowl as a rookie with the Cardinals in 2008, ranked second among running back in receptions (63) in 2009 and averaged a career-best 4.8 yards a carry in 2010 before his knee injury the next season sent him on a odyssey searching for medical answers.
His rehabilitation was complicated by an infection that wasn’t discovered until two years after his injury and Hightower often wondered whether his career ended when he was 25.
During his ordeal, Hightower underwent multiple surgeries, while accumulating countless frequent-flyer miles.
“I was flying around to every single doctor trying to find an answer,” Hightower said. “I was all over the place. I probably touched 20 of the 50 states just trying to find a solution.”
Hightower spent his abbreviated 2011 season as the starter in Washington with 49ers head coach Kyle Shanahan, who was the offensive coordinator, and 49ers running backs coach Bobby Turner.
Shanahan was impressed. With the Browns in 2014, he reached out to Hightower, who was still recovering. He also expressed interest in bringing Hightower in 2015 when he was with the Falcons.
“Usually when you take a few years off, and your knee is like that, it’s very hard to come back,” Shanahan said. “But if anybody knows Tim — he’s a guy you never count out.”
Hightower’s intangibles were part of the attraction to the 49ers.
He’s the elder statesman of a position group in which the other players have an average age of 23.8 years. General manager John Lynch has hailed Hightower’s professionalism and the way he takes care of his body, suggesting it’s rubbed off on Hyde.
Turner calls Hightower a “pro” and the way he emphasizes the word makes it clear it’s meant as the highest praise. Hightower says he was fortunate to learn from legends at an early age: As a rookie, his Arizona teammates includes Kurt Warner, Edgerrin James, Anquan Boldin and Larry Fitzgerald.
Turner agreed with the idea that Hightower is akin to a junior assistant coach.
“Tim’s the glue,” Turner said. “He’s an extension of my arm. I’m an extension of coach Shanahan’s arm. So, as far as the running backs and our meetings, he brings it every day.”
However, Turner makes it clear that Hightower was signed to play meaningful snaps, not merely be a mentor.
“I don’t go by age,” Turner said. “I go by what a guy does. The bottom line is Tim’s still productive.”
For his part, Hightower wants to have the most productive season of his one-of-a-kind career. He understands the interest in his past, but he’s eager to add even more memorable chapters to his comeback story.
“I’ve got a lot more that I want to do,” he said. “I’ll reflect on it one day with my kids. Now is not the time to reflect.”
Eric Branch is a San Francisco Chronicle staff writer. Email: EBranch@sfchronicle.com Twitter: @Eric_Branch