INGLEWOOD, Calif. — Preliminary tests revealed that Los Angeles Chargers running back Najee Harris suffered an Achilles injury during Sunday’s 23-20 win against the Denver Broncos, coach Jim Harbaugh said after the game.

Harris collapsed on a play-action play in the second quarter and immediately grabbed his left calf. The Chargers initially said he was questionable to return with an ankle injury before later ruling him out.

Harbaugh said Harris will undergo additional testing to determine the severity of the injury.

He added that he spoke with Harris at halftime and encouraged the veteran running back that he would be back on the field and in good shape in no time. Harbaugh said that Harris wasn’t dejected, describing his demeanor as “cold-blooded.”

Harris had a team-high 28 yards on six carries before exiting. In his place, first-round draft pick Omarion Hampton had the best game of his career, finishing with 129 yards from scrimmage and his first career touchdown.

“Man, what a game he had. How about that?” Harbaugh said. “He put that work in today, and he was running with a purpose. Gritty performance by him. Just always lunging forward, surging forward.”

Hampton said he texted Harris and wished him a speedy recovery. He also acknowledged how his role might change with Harris out.

“I definitely got to step up,” Hampton said.

Hampton played a career-high 63 snaps against the Broncos; his backup, Hassan Haskins, played just six. It’s a sign Hampton could be the lead back for the Chargers moving forward if Harris misses significant time. The Chargers also could look to elevate Kimani Vidal or Amar Johnson from the practice squad or sign a free agent to keep Hampton from wearing down.

Offensive coordinator Greg Roman has historically split carries between his top two or three running backs. During the preseason, when Harris’ status for Week 1 was in doubt due to a July 4 fireworks mishap, Roman said Hampton would split carries with whichever running backs were active.

Harris, who signed as a free agent with the Chargers in March, landed on the non-football injury/illness list ahead of training camp after the fireworks accident. He missed all the Chargers’ training camp practices but was ready for the beginning of the season. The Chargers had been increasing Harris’ workload each week, and Sunday, he appeared on track for his most carries and most productive game this season.

Harris has never missed a game in his NFL career, and his durability is one reason he was attractive to the Chargers.

Harris rushed for 1,000 yards in each of his first four seasons with the Pittsburgh Steelers. His physical style of running is one that Harbaugh covets, and having him to start the season was crucial for this team’s ceiling in 2025.

“It’s always too tough to lose a brother like that,” quarterback Justin Herbert said. “And I think you never want to see that from any of your own players or an opponent, and we’re wishing for the best.”

Also Sunday, Chargers offensive lineman Mekhi Becton left with a concussion and is now in the protocol, according to Harbaugh.