James Conner carted off after potentially serious leg injury

The Cardinals may be dealing with a serious injury to their starting running back.

James Conner was carted off the field after suffering a right leg injury during the third quarter of Sunday's contest against the 49ers.

Conner went down after a 1-yard run up the middle early in the third quarter. He immediately grabbed his lower right leg after he was hit awkwardly by the San Francisco defense.

Conner rushed for 73 yards with a touchdown in Arizona's first two games this season. He also entered Sunday with five catches for 23 yards with a TD.

He ends Sunday's contest with 22 yards on nine carries plus 15 yards on three receptions.

Update 6:15 p.m. ET: Conner was quickly ruled out with an ankle injury.