AMES, Iowa (AP) – Iowa State running back Shontrelle Johnson may be gone for the rest of the season because of a neck injury. Johnson injured his neck in a loss to Texas on Oct. 1 and has missed the last two games. Coach Paul Rhoads said Monday that the medical staff hasn’t decided yet how to treat the injury. Johnson was the Cyclones’ leading rusher when he got hurt. The 5-foot-9, 187-pound sophomore has carried 51 times for 247 yards, an average of 4.8 yards a carry. Sophomore James White has played most of the time at running back since Johnson’s injury. White rushed for 148 yards at Baylor on Oct. 8 and had 61 yards in 14 carries at Missouri on Saturday.