Eric Henderson barely had settled into his office at USC before Bear Alexander appeared in the new defensive line coach’s doorway.

“He was one of the first people I laid eyes on,” said Henderson, who traded the NFL’s Rams for the Trojans in January.

Henderson already had an inkling of what USC’s top defensive lineman could do. He’d kept tabs on some top defensive line prospects while on the Rams staff, and Alexander, a 315-pound human wrecking ball and former five-star recruit, had caught his attention. Alexander’s first year at USC, after transferring from Georgia, had been filled with flashes of ferocious, unblockable brilliance. But those flashes of greatness often faded into prolonged uneven stretches, and Alexander finished with just 1½ sacks and 6½ tackles for loss.

“He’s shown that he’s got the ability to be an explosive player, but he’s also been a player that his inconsistencies have hurt us, like any player’s inconsistencies are going to hurt you,” USC coach Lincoln Riley said last week. “So whether it’s effort all the time, whether it’s being in the correct gap, playing blocks the way we want to play them and aligning correctly, I feel like all those little things [are] where you step up from being a guy that flashes to a guy what I’d truly term a great player.”

USC needs more from its star defensive tackle, if it hopes to hold up in the Big Ten. Henderson knew that much when he took the job. Yet as concerns swirled about his effort, here was Alexander at his new coach’s door, asking questions, eager to learn. He came back again. And again. Motivation, Henderson figured, didn’t appear to be the problem.

“I can’t get him out of my office,” Henderson said. “He’s a guy that’s been thirsting for knowledge. You love that. Any time you have guys like that, you want him to have success.”

And Henderson understood, better than most, what that would take with Alexander. Not only did Henderson have a track record training top linemen such as future Hall of Famer Aaron Donald, but he could relate on a deeper level with Alexander, through hardships they both endured in their upbringings.

Soon after Alexander started showing up at his office, Henderson started opening up to Alexander about his own path and those obstacles he’d overcome. Henderson tried to show each of his defensive linemen his vulnerable side — to give them a piece of himself, in hopes they’d offer up part of themselves in return.

It was the only way he knew how to coach, Henderson said. To Alexander, it meant a lot to connect on that level.

“I really can relate to Coach Henny, his story,” Alexander said. “We shared with each other, where he’s from, where I’m from.”

A strong relationship was forged from those meetings in Henderson’s office, but it wasn’t long before their bond would be tested. In April, with spring practice underway, Alexander told USC coaches he intended to enter the transfer portal.

Henderson and his NFL pedigree would play a critical role in convincing Alexander not to leave.

“He didn’t. So we’re glad he’s still here,” Henderson said. “We do not want to relive whatever that was at that time.”

Henderson didn’t have much chance to work with Alexander in the spring, as the defensive tackle sat out most of April because of a nagging hamstring injury. The injury left him behind in picking up USC’s new defensive scheme and understanding his role in it.

So through the summer, Alexander spent as much time as he could with Henderson, “going over the ins and the outs of the game, what’s good, what’s bad, making sure we’re putting everything on the table,” Alexander said. Out of those sessions, he came away with at least some understanding of what was holding him back. He spent time with Henderson learning defense on a deeper level. He tried to focus on finishing plays and keeping up his energy through an entire game.

He didn’t want to be the guy who just flashed anymore.

“No flashing,” Alexander said. “Just being a consistent player, making sure I’m well-rounded in all areas … just making sure my motor is at the top so other guys’ motors are as well.”

USC’s defensive front might go only as far as that motor can take it. There’s not much in the way of proven depth behind Alexander, outside of experienced transfers like Nate Clifton (Vanderbilt) and Gavin Meyer (Wyoming). Last week, when asked how important it is for USC that Alexander become a more consistent force along the defensive front, Riley didn’t mince words.

“It’s real important,” Riley said. “We need him to take more steps in that direction, and I think he’s got great intent to do it. But this stretch for him is going to be very, very important.”

There are signs that Alexander is heeding that call. Starting with a newfound focus, he said, on “making sure I’m constantly a vocal leader” and mentor for USC’s freshman defensive linemen, two roles he’d never shown much interest in before.

Henderson has witnessed that shift firsthand, manifested over summer meetings in his office. But he knows better than most that Alexander still has a distance to go before he scrapes his ceiling.

“He continues to get better,” Henderson said. But, he added, “we’re nowhere near where we want to be obviously.”