Source: Cardinals TE Zach Ertz (knee) out indefinitely

TEMPE, Ariz. -- Arizona Cardinals tight end Zach Ertz is out indefinitely with a knee injury suffered early in Sunday's win over the Los Angeles Rams, but he will get a second opinion, a sourced told ESPN's Adam Schefter.

The injury could be season-ending.

Cardinals coach Kliff Kingsbury said during his press conference Monday that the team expected to have a better picture of Ertz's injury later Monday or sometime Tuesday.

Ertz went down in the first quarter and walked off gingerly under his own power but put his head in his hands in one point. Teammates came over to him to slap his shoulder pads and give him high fives in support. After being evaluated in the blue medical tent, Ertz was carted to the locker room.

Ertz had 406 yards and four touchdowns on a team-high 47 catches before his injury.

Also Monday, the Cardinals released running back Eno Benjamin, who filled in as their top rushing option while James Conner missed three games earlier this season. Benjamin saw his first significant game action this season. Drafted in the seventh round out of Arizona State in 2020, Benjamin didn't play his rookie season and then had just 34 carries for 118 yards in nine games last season.

He already had 70 carries for 299 yards and two touchdowns this season but he didn't have a single carry in Sunday's win over the Rams in just one offensive snap.

Kingsbury said Monday that the reason for Benjamin's reduced role was the improved health of Conner.

"We talked about James getting the full share, if you will," Kingsbury said. "I mean, he's been banged up, had the ribs and it was basically one of those deals where it was time to give him the starting running back reps and I thought he played at a high level and got better as the game went on, allowed him to get in a rhythm and did what we needed him to do."