CeeDee Lamb took a big hit and committed a penalty in the Dallas Cowboys’ preseason opener — even though the star receiver wasn’t playing.

During the second quarter of the Cowboys’ 31-21 defeat against the Los Angeles Rams on Saturday night, a sprinting official accidentally collided with Lamb’s back. The four-time Pro Bowl receiver had strayed too close to the field, which led to a 15-yard penalty against Dallas for contacting an official.

Clad in casual attire, Lamb was observing Joe Milton’s long throw to Jonathan Mingo and gesturing to his teammates as he stood on the sideline’s boundary marked by white paint.

The official, focused on following the play, didn’t notice Lamb and unintentionally ran into him, causing both to fall to the turf at SoFi Stadium.

“It’s a sideline interference,” referee Alex Moore told a pool reporter.

“CeeDee Lamb was standing in the restricted white border area, which is our area to officiate the game. The official on the play was focused solely on doing his job and he ran into CeeDee Lamb, who was standing in that restricted area. That’s what happened. And with that contact, it’s an automatic foul.”

Lamb got up with no apparent ill effects, laughing about the collision with his teammates.

Dallas was still whistled for the penalty, which took 15 yards off the Cowboys’ 51-yard gain on Los Angeles defensive back Shaun Jolly’s simultaneous pass interference on Mingo.

“Normally we don’t have anybody standing that deep into the restricted area, or that type of forceful contact,” Moore said. “So it is a rare occurrence, but it does happen from time to time.”

Dallas coach Brian Schottenheimer wasn’t thrilled about Lamb’s mistake, even though he knew it was an accident.

“Just like the pre-snap penalties, that penalty, we’ve got to be better with discipline,” Schottenheimer said. “I hope the guy’s OK. I think he’s OK, the official that he ran into, but we have to be better than that. CeeDee knows better. We know better.”

Lamb, Dak Prescott, George Pickens and most of the Cowboys’ key players didn’t participate in the preseason opener, nor did nearly all of the Rams’ presumptive starters.