Arizona Cardinals star running back David Johnson is not expected to play Thursday night against the San Francisco 49ers, a source told ESPN's Adam Schefter.
The absence of Johnson, who officially is listed as questionable, means that newly acquired Kenyan Drake likely will have a prominent role against the undefeated Niners' top-ranked defense.
The Cardinals, who already are without injured backup Chase Edmonds, listed Johnson as questionable after the former Pro Bowler was limited in Wednesday's practice.
Cardinals coach Kliff Kingsbury was coy Wednesday when asked about Johnson's chances to play, saying he was "working through it" while acknowledging that Arizona would use a "running back by committee" against the Niners.
The Cardinals' running back depth chart Thursday night will include three players not on the roster at the start of last week: Drake, Zach Zenner and Alfred Morris.
Arizona acquired Drake on Monday from the Miami Dolphins after signing both Zenner and Morris last week. Morris will be active against the Niners, Kingsbury said, after being a healthy scratch against the New Orleans Saints in Week 8.
Drake, who arrived in Arizona at 4 p.m. local time Monday and had a playbook in his hands by 7 p.m., has been forced to learn the Cardinals' scheme on the fly. Kingsbury admitted it's challenging to have a new running back playing with such a short time in the system, but it's up to the Arizona coaching staff to have Drake do only what he can handle and feel comfortable with.
Johnson, 27, has rushed for 300 yards and two touchdowns is seven games this season, his fifth with the Cardinals. He is also Arizona's third-leading receiver with 30 catches for 315 yards and three touchdowns.
ESPN's Josh Weinfuss contributed to this report.