Valdez, 33, is a career .243 / .290 / .330 hitter and has missed at least two full years in the majors since his debut in 2004. That said, Valdez has played in 111 and 99 games the past two seasons, and could add a touch of depth to the middle infield.
Horst, 26, is a lefty reliever that only has 15 big league innings to his name, but they were good ones. He has a 2.93 ERA, though he did give up two home runs over the course of 12 games. Regardless, don't take too much stock into his current stats until the Phillies give him more than a cup of coffee.