USC football’s injury report got its most prominent addition in Day 4 of fall camp, when star outside linebacker Porter Gustin was carted off with a knee injury.

The injury bug never ceases to prey on players in fall camp, and on Day 4, that meant bad news for USC football’s own predator on defense, Porter Gustin.

‪The senior outside linebacker tweaked his knee during a team-run session of practice Tuesday afternoon.

After attempting to get up and walk it off, Gustin needed assistance leaving the field of play and was eventually carted off to the McKay Center, following a sideline examination from USC’s training staff.

He wasn’t able to put any weight on his leg, requiring a tag-team effort to get him situated on the cart. With Gustin shut down, true freshman Kana’i Mauga took over at the predator position.

After practice, USC head coach Clay Helton said Gustin will undergo an MRI, but ironically wasn’t in pain, with his knee feeling ‘funny’ instead.

“The knee seems stable,” Helton said. “But let me wait until I get the MRI before I start guessing [the severity].”

Gustin, who was named to the 2018 Butkus Award watch list in July, missed 10 games last season following injuries to both his upper and lower body, including a broken foot and torn biceps.

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Since leading the team with 13 tackles for loss as a sophomore in 2016, he’s been expected to be a key figure in the Trojans’ defense, particular this upcoming season following the graduation of acclaimed linebacker Uchenna Nwosu opposite of him.

Should this ailment be another significant one for Gustin, USC’s huge six-man linebacker haul in the 2018 recruiting class could get their opportunity to see the field early, despite the Trojans boasting four returning starters. But for now, USC will wait around for good news.

USC Football Injury Report:

Out for the season: LB Tayler Katoa (LDS Mission)

LB Tayler Katoa (LDS Mission) Out: LB Oluwole Betiku (hip), LB Porter Gustin (knee), LB Levi Jones (chest), TE Erik Krommenhoek (hamstring), S Ykili Ross (hamstring), WR Jake Russell (leg), LB Cameron Smith (hamstring), LB Solomon Tuliaupupu (foot)

LB Oluwole Betiku (hip), LB Porter Gustin (knee), LB Levi Jones (chest), TE Erik Krommenhoek (hamstring), S Ykili Ross (hamstring), WR Jake Russell (leg), LB Cameron Smith (hamstring), LB Solomon Tuliaupupu (foot) Questionable: OL Chuma Edoga (hip), CB Je’Quari Godfrey (hip)

For the first time during fall camp, USC will dress in full pads on Wednesday. Due to conference rules, they were mandated to gradually built up to full pads, which explains the last two days of shells — shoulder pads and helmets, with shorts.

UPDATE:

Right tackle Chuma Edoga and cornerback Je’Quari Godrey were both pulled from practice on Tuesday with hip soreness.

Edoga’s first team spot was filled by both Clayton Johnston and Jalen McKenzie.

With Godfrey out, freshman Chase Williams and others saw extra reps.

Linebacker Levi Jones sat out practice with chest swelling. The swelling is internal and in the area of his heart, but doctors are certain it is not a coronary issue. Still, he will be held out until the swelling comes down.

Meanwhile, Erik Krommenhoek remained out with hamstring tightness which cropped up on Monday.