Vikings star defensive end Jared Allen left practice Tuesday with an ankle injury. Allen will undergo further exams to determine the severity of the injury. Head coach Leslie Frazier says he believed the injury was nothing to be overly concerned about. In other team news, the Vikings signed linebacker Stanford Keglar and released linebacker Nathan Williams. The Vikings open up preseason play against the Houston Texans on Friday at the Metrodome. Catch all the action on SAM 107.3.