Colorado bolstered its bullpen with Lopez. The 29-year-old righty was 6-3 with 10 saves and a 2.17 ERA in 64 games for the Astros. He struck out 54 and walked only eight in 66 1-3 innings.
The 24-year-old White split last season with the Rockies and Triple-A Colorado Springs. He was 2-9 with a 5.51 ERA in 23 games for the Rockies, including 20 starts.
The 23-year-old Gillingham was 6-8 with a 3.66 ERA at Class-A Asheville in his first full pro season.
AP Sports Writer Mike Fitzpatrick in New York contributed to this report.