Veteran first baseman Todd Helton launched a two-run shot to center in the first inning off Padres starter Freddy Garcia for his second homer of Cactus League play. Then Rosario, who homered off the Giants' Matt Cain on Thursday and the Rangers' Ben Rowen on Friday, took Garcia deep to left field on Saturday night.
"I told [Rosario] to keep hitting them as long as he doesn't use them all up this spring," Rockies manager Walt Weiss said. "He's got big-time power. He's going to be able to hit the ball out of the park no matter where we play, and he's going to be able to do it pretty consistently."
Rockies second baseman Josh Rutledge led off the second inning with a homer off Garcia.
The Rockies scratched scheduled starter Jorge De La Rosa on Saturday afternoon because of left forearm tightness. Right-hander Jeff Manship started, pitched three innings, struck out three and gave up two runs on two hits -- Kyle Blanks' single, followed by Nick Hundley's homer in the second.
Righty Jhoulys Chacin, who was supposed to start Friday but was pushed back because of back spasms, made a two-inning appearance and gave up two solo shots. The first was in the fourth to Blanks -- who could break camp with the Padres if outfielder Carlos Quentin's knee injury forces him to the disabled list -- and the other was to non-roster invitee Cody Ransom in the fifth.
Garcia, on the fringe of the competition for the Padres' rotation, didn't help his cause by giving up seven runs (three earned) on five hits and three walks in five innings.
Reserve catcher Gustavo Molina added a fourth homer for the Rockies, connecting for a three-run shot off Brad Brach in the seventh.
Up next: Right-hander Juan Nicasio will start for the Rockies against the Brewers at Maryvale Baseball Park on Sunday at 2:05 p.m. MT with coverage on MLB.TV. De La Rosa, who was scratched Saturday night, will pitch two innings in a Minor League game at Salt River Fields at Talking Stick.
Thomas Harding is a reporter for MLB.com. Read his blog, Hardball in the Rockies, and follow him on Twitter @harding_at_mlb. This story was not subject to the approval of Major League Baseball or its clubs.