From CNN:
"It was a wild Signing Day for San Antonio, Texas four star linebacker Travis Lewis. Lewis had originally committed to Nebraska, but recently switched to Oklahoma. The 6-foot-1, 213-pounder is ranked the No. 37 player in Texas and is ranked No. 20 among outside linebackers."
With OU already having 2 of the top LB prospects (the Rivals No. 3 High School OLB and a five star JUCO) signed and no RBs perhaps that rumor about him playing RB makes sense. Perhaps he figures he's only a couple of injuries away from being the starting running back at OU whereas at Nebraska, maybe 6 guys would be in front of him on the depth chart at RB.