Shortstop Brandon Wood was 3-for-3 for the Rockies with a single, double and triple. Charlie Blackmon's single and Wood's triple in the sixth inning ended the Rockies' 14-inning scoreless stretch against the Royals, who were 5-0 winners on Thursday.
Mendoza gave up two hits -- both by Wood. But he was the only baserunner as Mendoza posted three strikeouts and got eight ground-ball outs.
"My sinker was there and I work a lot inside with the lefties, and I throw my sinker outside and I had success with that," said Mendoza, who has six scoreless innings so far this spring. "My sinker for strikes is going to be good."
The Royals picked up one run against Rockies starter Jhoulys Chacin in the last of his three innings. Alcides Escobar bunted safely and scored on Alex Gordon's double to deep center field.
'I'm really happy I threw my fastball for a strike and I didn't walk any guys -- that was what I was working for," Chacin said. "Throwing my fastball where I want to is the key for me, and I'm starting to use my breaking ball more."
Against left-hander Christian Friedrich in the fourth, the Royals loaded the bases on singles by Mike Moustakas and Jeff Francoeur and Lorenzo Cain's walk. Two runs scored as Escobar's high bouncer was grabbed and thrown away by third baseman Nolan Arenado, a hit and an error.
Friedrich also was the victim of Butler's home run, a shot into the left-field bullpen. It followed a single by Eric Hosmer. Butler also doubled in the second inning and raised his average to .467 (7-for-15).
It was the fifth straight loss for the Rockies, who are 1-5-1. The Royals improved to 5-3.
Up next for the Rockies: The Rockies have a split-squad Sunday, with rotation candidates starting both games. Left-hander Jamie Moyer will start against the White Sox at Salt River Fields at Talking Stock. Righty Guillermo Moscoso also will work that game. Right-hander Alex White will start against the Brewers at Maryvale Baseball Park.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.