The Diamondbacks came away empty-handed during a three-game series against the Houston Astros, after returning from the All-Star break with three consecutive victories over the St. Louis Cardinals. Arizona will turn to right-hander Ryne Nelson (6-2, 3.52 ERA) on Friday, opposite Pittsburgh rookie right-hander Mike Burrows (1-3, 4.70). The Pirates are not in postseason contention and are likely to be sellers approaching the July 31 trade deadline.