The Rule: "When sliding into a base in an attempt to break up a double play, a runner has to make a "bona fide slide." Such is defined as the runner making contact with the ground before reaching the base, being able to reach the base with a hand or foot, being able to remain on the base at the completion of the slide (except at home plate) and not changing his path for the purpose of initiating contact with a fielder. The slide rule prohibits runners from using a "roll block" or attempting to initiate contact with the fielder by elevating and kicking his leg above the fielder's knee, throwing his arm or his upper body or grabbing the fielder. When a violation of the slide rule occurs, the offending runner and the batter-runner will be called out."
Looking at the rule Garver both over slide the bag and threw his upper body at the fielder.