Running back Joe McKnight is expected to share the load in the running game with Stafon Johnson. McKnight has had a setback in that regard, suffering a hyperextended elbow during a scrimmage on Saturday.McKnight missed practice on Sunday, and could miss more time."It’s not damaged or anything like that,” coach Pete Carroll said. “I don’t think it will be but a couple of days."McKnight has had other injuries as he makes the transition to full-time running back. As a freshman, he played tailback and receiver.