Tim Hightower had enough.

He tried to maintain a positive outlook and find new ways to keep hope alive during his nearly four-year comeback from a torn ACL.

But his knee seemed to keep finding even newer ways to trip him up, and on this day he considered hanging it up.

Though it wasn’t a common occurrence, it wasn’t the first time the thought slithered from the back of his mind, constricting him with doubt.

He was getting too old. He had been out of the game for too long to make it back. His knee wouldn’t cooperate, and no one could figure out why. The road was getting too bumpy — too many potholes, too many false starts. Maybe it was time to turn the idling ignition off, take the key out and throw it away forever.

Hightower, 29, picked up the phone and called his wife, Rikki. Frustration guided his words. He told her how he felt. He doubted his future, his ability to get back into the NFL, he said.

But she didn’t want to hear it.

“Hey, this is what you said you were going to do,” she told him. “It’s not about money; it’s not about any of these things. It’s about (how) you made a commitment to yourself, you made a commitment to your family and (you have) to see it through.”

It would be a falsehood to paint this as the Hollywood moment when the music started playing in the background as Hightower perked up and stormed back into the gym a reinvigorated man. But that kind of support during a dark period in his life is what eventually led Hightower back into the NFL as a member of the New Orleans Saints.

In truth, it still somewhat shocks him that he’s back in this position.

The last time Hightower played football in the Superdome was during a 2009 playoff game when his Arizona Cardinals faced the Saints. For a brief moment, it looked like he was going to carry his overmatched Cardinals to victory: He took a handoff and ran 70 yards for a touchdown on the first play from scrimmage.

As he glided into the end zone, Hightower likely felt like he was experiencing a signature moment in his young career. It didn’t matter that New Orleans eventually won 45-14 en route to claiming the Super Bowl. Hightower’s run was the kind of play that can propel players to the next level.

In some ways, that thinking would have been correct. He collected 872 yards from scrimmage the next year. But what he didn’t know is that he was actually running toward one of the more trying periods of his life with each step. Hightower was traded to the Washington Redskins during the 2011 offseason, which signaled the beginning of most frustrating chapter of his football life.

When Hightower first tore the ACL in his left knee Oct. 23, 2011, against the Carolina Panthers, he didn’t think it was a big deal. It was a setback, but he assumed he’d be back by the start of the next season.

No big deal, he figured.

“You think ACLs these days is a pretty routine surgery,” Hightower said. “You got great doctors. Guys come back in six months.”

After an attempt to repair his knee, he began rehabbing about a month later and then took part in the Redskins’ training camp. He appeared in one game that preseason, logging five carries for 28 yards. He was cut weeks later in advance of the 2012 season opener against the Saints. There were some tryouts along the way, but he remained out of football until hooking on with New Orleans.

The issue is that his knee was never quite right. It’d be fine one day and swell up the next. He didn’t understand what was going on. He’d meet with one doctor and then the next. No one had answers.

“To go from never missing a game, never missing a practice, being real durable, to, ‘What’s going on with my body? Is this how I’m going to be the rest of my life?’ ” Hightower said. “It was scary to not have answers.”

Through it all, he never stopped working toward his goal of getting back to the NFL, even if his knee didn’t cooperate. There were moments of doubt, like the one that led him to call his wife, but he never actually stopped trying or surrendered on rehab. Hightower kept going to doctors, and they finally figured out that an infection was causing all of his issues.

Another surgery, the doctors said. Then, Hightower finally started to feel normal again.

After years of saying he wasn’t healthy when teams called, he could finally accept invitations to tryouts. He visited the Giants in 2013 and then the Redskins last season. Yet nothing worked out. Hightower began to wonder whether he was ever going to get a chance to get back in the league. Then, finally, the Saints gave him a shot in January by signing him to a reserve/futures contract.

It felt surreal when he finally touched a football as a member of an NFL team during organized team activities.

“I was nervous and very anxious to get going, carry a football, catch a football,” Hightower said. “A lot of emotions that I hadn’t felt before, something that I used to feel, that came back. A lot of excitement.”

It still feels odd, and Hightower knows it’s going to take some time for things to feel natural again. His timing feels off. It’s weird to hear play calls and experience the flow of the game. It doesn’t yet feel natural when he makes cuts. But each day a little more rust falls off, and the running back feels a little more natural on the field.

The main thing is that he doesn’t worry about his knee. It hasn’t swollen. He actually thinks it’s stronger than the other one. But Hightower is still waiting to fully test himself, and that won’t happen until he can finally take some hits at training camp and get back into the flow of things.

“It’s like a boxer,” Hightower said. “You know a boxer can’t go in the ring without getting hit a couple of times. It’s kind of the same thing.”

Some might doubt his ability to stage a comeback after such a long layoff, but Hightower doesn’t expect this to be a short visit. He did too much to get here. He plans to fight with everything he has to make the 53-man roster. He doesn’t care how he does it.

When discussing a potential role, he brought up his time playing college football at Richmond. That’s when Hightower would have to run down the field and cover a kickoff after breaking a long run for a touchdown.

He doesn’t care about glamour. He just wants a job.

But that’s Plan B. He wants more for himself.

“(I expect) to come here, learn this offense, get a good feel for it,” he said. “But I plan on being here, I plan on being here this season, on this team. Getting back to success they’ve had on offense and hopefully the success they’ve had in the past.

“My expectation is not to just go out here and just be a guy, but to go out here and be one of the key guys.”

Cracking the roster will be a difficult task with all of the talent the Saints have at running back. But after the odds Hightower overcame just to get here, it might not be wise to bet against him, knowing he has set his mind to the task.