"I know last year, every time I [went] out there -- bam-bam-bam-bam-bam," Corpas said. "But that was last year."
Corpas experienced "bam" in a different manner in the seventh inning against the Cubs on Friday afternoon. "Bam" went Jim Edmonds' two-run double, and "bam-bam" went a two-run Mark DeRosa homer that gave the Cubs a 10-9 victory and completed the Rockies' collapse after having held an eight-run lead.
It happened just as Corpas appeared to be turning around his season.
Corpas, the almost-untouchable closer for last year's National League champs, lost his job to Brian Fuentes in April and gave up runs in nine of his first 16 appearances. But he went into Friday having not allowed an earned run in 10 games and no runs at all in eight.
Corpas has had consistent movement on his sinking fastball, but the slider, which hasn't reached a state of consistency all season, left him again on the three hits he gave up on Friday, including the Kosuke Fukudome single that was sandwich between the double and the homer.
"I was not staying on top of the ball," Corpas said. "Yesterday, I don't know what happened. When I throw my best pitch, I get double plays. But sometimes you have good days, sometimes you have bad days."
The Rockies, who signed Corpas, 25, to a four-year contract guaranteeing $8.025 million before the season, need him to return to a late-innings role. Manager Clint Hurdle said he's now looking for Corpas to pitch extended innings to give him more pitches to complete his resurgence.
"Yesterday, he had two left-handers and a right-hander, and it was more of what we saw a month ago than what we've seen the last two weeks," Hurdle said. "It's unfortunate. His pitches are telling me what he's doing and what he isn't doing."
Corpas said he believes he can return to last year's level of confidence and competence.
"This year is a new year," Corpas said. "I'm OK. I'm ready. It's a long season."
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.