It’s hair today, gone (for touchdowns) tomorrow for USC’s Ronald Jones II

If prompted, Ronald Jones II can produce a bag containing a prodigious set of dreadlocks, which he keeps at his residence.

They are his — or used to be. He cut his hair this summer and couldn’t summon the will to discard the locks.

By the middle of USC’s season, he was glad they were still around. Jones was struggling, and no one could crack the puzzle. He looked a little impatient. His vision was off. But why? After one game, he suggested to reporters that it was the hair. Everyone laughed. Jones, it turned out, was not joking.

“I was thinking about reattaching it to give me my strength,” Jones said, sitting outside USC’s football facilities one day this week. He did not laugh.

“We kind of compared it to Samson in the Bible,” his mother, Jackie Jones, confirmed. “He really thought that.”

Jones, USC’s explosive starting tailback, knows what makes him happy. He likes the Texas fast-food chain Whataburger. He likes to run the football. And he liked his dreads.

When Jones is happy and confident, he has been nearly impossible to stop. He has averaged 152 yards per game over USC’s last four games, and he is 107 away from 1,000 on the season. Getting that confidence has been the only tricky part.

As a freshman last season, Jones, who is from Dallas, missed some early fall practices because of homesickness. It wasn’t that he was lonely so much as physically ill.

“I wasn’t breathing straight, I wasn’t thinking right,” he said. “I don’t know, it was just something triggered. I would literally get dizzy, and I wouldn’t know what was going on. My judgment was off. My vision was blurry. The sun seemed extra bright.”

The doctor thought the new locale might have aggravated Jones’ allergies, but Jones thought it was more than that. He’d been excited to leave home. Jones is the second eldest of five siblings. Jackie Jones, a social worker for 15 years, adopted his three younger siblings, survivors of Hurricane Katrina. Jones was counted on to help out.

Jackie bought him a car when he was 15, and even though he was too young to legally drive, he’d ferry his brother and sisters to track practice, basketball practice, leadership classes. He was responsible for ironing his brother’s clothes. He told his mother he couldn’t wait to get to school and never iron again.

But when he arrived, the change was a lot. Schoolwork was grueling. The food was new and strange.

When Jones, feeling better, returned to practice, he told reporters that his problem was a Whataburger deficiency, and he wasn’t joking this time, either.

In Los Angeles, he said, “it was a bunch of sushi and stuff. I had never tried it. But I was open, I tried a California roll. I didn’t like it.”

Two things helped. When his mother would visit for games, she began picking up his usual Whataburger order at the airport in Dallas: two patty melts, onion rings and, sometimes, a Fanta strawberry. She still brings it each time she visits, though Jones has now found some suitable replacements in Los Angeles.

And Jones began sessions with one of USC’s sports psychologists, where he discussed his anxiety and, over the course of a couple months, began to feel more comfortable.

His adjustment on the field was less stressful; He set USC’s freshman rushing record last season with his dreadlocks flapping against his shoulder pads, as if waving goodbye to chasing defenders.

His homesickness had been vanquished when, during the off-season, he and his mother made a wager over an NFL game. Jackie had been fixing to cut Jones’ hair. She thought a closer crop would look cleaner, more professional. So that was the wager.

Jones lost. He cut the dreadlocks himself during summer practices, then had a barber trim up the rest.

Jones had been growing the dreads since eighth grade, a nod to his Jamaican heritage. Once, they’d been even longer, but high school opponents would grab hold of them and try to drag him down, so he cut them to shoulder length. Jones, a track star in high school, said they made him feel fast and strong.

“In the black community, we say our hair is our crown,” Jackie Jones said. “It’s a symbol of pride.”

Without the dreadlocks, Jones said, “I wasn’t sure if I would be the same player.”

The universe seemed to provide him with confirmation. Jones, playing behind Justin Davis at the beginning of the season, averaged just 35 yards in the first six games.

Word eventually filtered back to USC Coach Clay Helton, who clutched his gut laughing this week when recalling the time he first heard of Jones’ theory. Helton has been coaching for a long time, but that was a first.

Helton, not given to much mysticism, wasn’t a believer. Jones’ uneven start was probably a result of inconsistent carries more than anything. His resurgence coincided with an injury to Davis that significantly increased Jones’ workload.

“So maybe he’s got his groove back after a couple hundred-yard games, that he’s learned he could do it without it,” Helton said of the hair.

Or is it just that Jones’ hair had some time to grow back? Jones said he’d probably regrow the dreadlocks, just to be safe.

Quick hits

Defensive tackle Josh Fatu (ankle) and defensive back Jonathan Lockett (hip) will be available to play on Saturday. ... Helton said he made an addition to his usual Thanksgiving meal: chicken wings. “We have a tradition on Thursdays, my wife makes wings for me,’ Helton said Thursday morning. “So she said on this streak, ‘Baby, we’re not changing this streak.’ So I think I’ve got wings today, too.”

zach.helfand@latimes.com

Follow Zach Helfand on Twitter @zhelfand