Losers of eight of 12, the Padres were routed 13-2 on Saturday.
“This shouldn’t happen this time of the year,” Padres center fielder Jay Payton said. “Every loss hurts and we know we have to win almost every game.”
San Diego is 2 1/2 games behind wild-card leaders San Francisco and Chicago with 20 games to play.
In Saturday’s loss, starter Adam Eaton gave up seven runs and a career-high 12 hits in five innings.
“Eaton had buzzard’s luck,” Padres manager Bruce Bochy said. “Not many hard hit balls, but a lot that found holes.”
After Sunday’s game, the Padres will continue their 11-game road trip with a four-game series with the NL West-leading Los Angeles Dodgers.
Garrett Atkins hit his first career homer, a two-run shot in the seventh inning, Barmes was 3-for-5 and every position player had a hit for Colorado, which has won seven of 10—all against teams still in the playoff race.