Detroit Lions running back Kerryon Johnson sprained his knee Sunday but doesn't need surgery and will be week-to-week, a source told ESPN's Adam Schefter.
The rookie, who has been one of the Lions' most dynamic players this season, injured the knee on a run where he started heading right, saw defenders and cut all the way back to the left side of the field before being tackled near the sideline for a 3-yard gain.
Johnson got up, went to the sidelines and was immediately looked at by Lions staff, first on the bench and then on the medical table behind the bench before heading to the locker room for further examination.