Los Angeles Chargers star Khalil Mack suffered a gruesome arm injury early in the teams game against the Las Vegas Raiders on Monday night.Mack and his teammate Troy Dye were chasing down Raiders wide receiver Tre Tucker toward the end of the first quarter. Macks left arm appeared to get jammed underneath Dye as they both went for the ball carrier.CLICK HERE FOR MORE SPORTS COVERAGE ON FOXNEWS.COMThe star pass-rusher immediately came out of the game as the quarter came to a close. The Chargers said initially that Mack was questionable to return due to an elbow injury, but was downgraded to out after he was seen on the sideline with his pads off and his arm in a sling.WARNING: GRAPHIC VIDEOThe Chargers were a top defense last season, finishing first in points allowed and 11th in yards allowed on their way to an 11-6 record and a wildcard berth.BAKER MAYFIELD AUTHORS INCREDIBLE FINAL DRIVE TO LIFT BUCS OVER TEXANSIt would be a huge blow for the Chargers defense should the team lose Mack for a significant amount of time. Chargers head coach Jim Harbaugh said Mack will undergo imaging tests.The Chargers won the game, 20-9.The linebacker earned the ninth Pro Bowl selection of his career last season with the Chargers and his fourth consecutive nod. He played in 16 games, recording six sacks and 39 tackles. He had nine pass breakups and two forced fumbles as well.Bud Dupree and Kyle Kennard were listed as Macks backups on the Chargers depth charts.Mack was traded to the Chargers before the 2022 season from the Chicago Bears. Hes considered to be one of the all-time greats at the linebacker position. He was named to the Pro Football Hall of Fames All-2010s Team.Follow Fox News Digitalssports coverage on X and subscribe to the Fox News Sports Huddle newsletter.