Twenty-eight days after tearing the ACL inside his left knee, LSU fullback J.D. Moore returned to work. His task: clear a lane for Leonard Fournette in a game his team already trailed a 10-0.

Fournette took a handoff, darting toward the left side of a massive Alabama defensive front that stifled him all evening in a 30-16 loss. Moore guided the Tigers’ Heisman Trophy candidate along, planting on a heavily braced left leg as 307-pound Crimson Tide defensive lineman Dalvin Tomlinson pursued.

Tomlinson flattened Moore to the turf, where the fullback’s six-game sophomore season, one that earned him a scholarship, came to an abrupt halt.

“There was no harm or foul to trying to play with it,” Moore, a former walk-on, said Thursday. “We were just trying to see if it was even a possibility because I wanted to just make sure I’d given every avenue a possibility before I decided to have surgery.”

“If you don’t have a good knee on a 300-pound All-American,” he added with a chuckle, “it’s not going to help.”

Moore first hurt the knee Oct. 10 after a South Carolina defender took out his knees following a completed pass. Moore underwent surgery days after the Alabama game.

It rendered him nearly immobile while his teammates endured the taxing end to a zany season, losing two of their final three regular-season games and, nearly their head coach.

Fournette’s production dipped, too, without his most valuable blocker. After mustering just 31 yards against Alabama, he averaged less than five yards per carry in losses to Ole Miss and Arkansas — games Moore watched from a recliner while elevating his injured knee.

“I don’t know if I’ll say that’s the direct cause,” Moore said, correlating his absence to Fournette’s struggles. “We faced a lot of really good teams on the back end of the year as well. It was a bummer being out, for sure, but (freshman) Bry’Kiethon (Mouton) did a great job stepping in as a true freshman.”

Mouton had heaps of help.

As soon as he was cleared to return to normalcy, Moore said he functioned as Mouton’s “second coach,” easing the burden of then-running backs coach Frank Wilson, who already split his time between position groups.

“Very coachable,” Moore said of his younger teammate, “and (Mouton) really embraced the role.”

Moore returned at “100 percent” Thursday as LSU opened preseason camp, running what coach Les Miles described as a “perfect” gauntlet drill in the veteran-heavy morning session without much trepidation.

“There’s not really a mental barrier for me,” Moore said. “Obviously we haven’t put on full pads yet, but I don’t think there will be. ... Those same sort of situations, the same sort of powerful impact that we’ll be doing with pads on — I’ve been able to do those perfectly fine over the summer, so I don’t think that will be an issue going into practice.”

When he does don pads, Moore will hone his fundamentals. The mental things, he says. How low his pads need to be when blocking. Precise hand placement. Getting good leg drive, especially when he plants that surgically mended one.

Thursday gave a promising start.

“Having a great summer. I can’t wait,” Miles said of Moore, an articulate, future architect, following the first day of camp. “He’s bright as a whip. Knows just what to do.”

Follow Chandler Rome on Twitter, @Chandler_Rome.