Abstract: Valve actuation systems are disclosed herein that allow valve opening timing to be varied using a cam phaser and that allow valve closing timing to be varied using a lost-motion system. In one embodiment, an actuation system is provided that has a locked configuration in which a bearing element is held in place between a cam and a rocker to transmit cam motion to an engine valve. The actuation system also has an unlocked configuration in which the bearing element is permitted to be at least partially ejected from between the cam and rocker, such that cam motion is not transmitted to the engine valve. The actuation system is switched to the unlocked configuration by draining fluid therefrom through a main valve which is piloted by a trigger valve. The actuation system also includes integrated autolash and seating control functionality.