The Chargers' ferocious defense may have to brace for the absence of one of its stars.

Pass rusher Khalil Mack suffered a gruesome elbow injury in Monday's 20-9 road win over the Raiders that knocked him out of the game and will require imaging Tuesday.

Mack exited the division matchup in the first quarter and wore a brace around his left arm after returning to the bench later in the night.

"We'll get some imaging tomorrow and see where that takes us," Chargers coach Jim Harbaugh said.

Mack, a 12th-year veteran, suffered the injury while attempting to tackle Tre Tucker in the first quarter.

While Mack extended and stuck out with his left arm, teammate Troy Dye collided with his arm and it bent at an unnatural angle.

Mack, 34, left the game in clear pain while grabbing his hand/arm area, and headed to the locker room.

The Chargers initially listed him as questionable before eventually downgrading him to out, though he later returned to watch the remainder of the team's second straight win over an AFC West team.

"We want to pick it up for him," Chargers safety Derwin James told ESPN after the game. "He even told us -- I said, 'Dang, Mack, you're out.' He say, 'Come on, DJ, keep going.' He wanted us to go keep finishing the game, we love him so much and we're going to have his back..."

The Chargers sit alone atop the AFC West in large part thanks to a defense that has stymied Patrick Mahomes' Chiefs and Geno Smith's Raiders in consecutive weeks.

They allowed just 21 points to the Chiefs in the opener before intercepting Smith three times and also tallying three sacks Monday while limiting the Raiders to 218 yards.

Mack tallied one of those sacks Monday, his first of the season, to give him 108 1/2 for his career.

If Mack has to miss any time, it would be a tough blow for a Chargers team already without star tackle Rashawn Slater after losing him to a season-ending injury during training camp.

Los Angeles continues its AFC West gauntlet to start the season Sunday when it welcomes the Broncos (1-2) before heading to MetLife Stadium to battle the Giants in Week 4.

Chargers star pass rusher Khalil Mack suffers gruesome arm injury in...