Louisville standout running back Isaac Brown was ruled out after the first half of the No. 24 Cardinals’ game against host Stanford on Saturday because of a shoulder contusion, the Louisville Courier-Journal reported.The true freshman was injured at the 6:29 mark of the first quarter and finished with three yards on two carries. The 5-foot-9, 190-pounder was seen leaving for the locker room with his right arm in a sling, according to media reports, and came out for warmups at halftime before being ruled out.Brown entered the day third in the FBS with 7.55 yards per carry, totaling 106 carries for 800 yards in nine games. He was tied for 37th in total rushing yards.