TEMPE, Ariz. — David Johnson’s first run in traffic was memorable, but not in a way that made his mother proud.
As a small child, Johnson, the Arizona Cardinals’ resplendent rookie running back, crossed a busy street with his sisters Danielle and Darnecia in Clinton, the Iowa town where they were raised. Upon finding out what they had done, Johnson’s mother delivered a tongue-lashing as severe as anything Johnson has absorbed from Cardinals Coach Bruce Arians.
In the second game of his N.F.L. career, Johnson ran into traffic and again emerged without a scratch, returning the opening kickoff against the Chicago Bears 108 yards for a touchdown.