But in the aftermath, he smiled and admitted his first rehab game at Triple-A Colorado Springs was frighteningly like "my first year in the rookie league."
Corpas can laugh now. He felt better in two subsequent outings. Before throwing a bullpen session Wednesday during a voluntary workout at Coors Field, Corpas proclaimed himself healthy.
Manager Jim Tracy agreed, and the team activated him Thursday before the opener of a four-game series against the Padres at PETCO Park. In a corresponding roster move, the Rockies designated right-handed reliever Matt Belisle for assignment.
"Obviously the last couple of times [Corpas] pitched on that brief rehab he had, he threw the ball extremely well," Tracy said. "We've had no repercussions whatsoever as far as the elbow is concerned. We'll move forward with that and take it a day at a time."
The Rockies could use Corpas' sound mind and arm.
Corpas (1-3, 5.40 ERA), the setup man for closer Huston Street, threw strong innings in close victories over the Rays on June 17 and 18. But he showed up June 19 with swelling and was unable to straighten his arm.
"[Before the injury] I think I was focused on the game well," Corpas said. "I wasn't trying too hard. I was making my pitches. I was keeping the ball low with my slider and my fastball. I felt good."
The injury came at a scary time for the Rockies. Corpas had a strong June, going 1-0 with a 3.00 ERA while tossing scoreless ball in seven of his nine outings, and Street had caught fire as the team's closer. However, the team had already lost setup man Taylor Buchholz for the season because of elbow surgery and had been doing without Ryan Speier because of leg, shoulder and delivery issues.
But right-handers Joel Peralta and Juan Rincon performed well in filling in for Corpas as setup men to keep the Rockies from having a crisis, and Street is 22-of-23 on save opportunities.
It isn't clear if Jim Tracy will put Corpas, 26, back into his old role immediately.
"I think I'm ready, but right now I don't know what will happen, because my friend [Peralta] is pitching good," said Corpas, who threw three scoreless outings, totaling 2 2/3 innings, with three strikeouts against two hits and one walk during his Minor League rehab outings. "I'm OK. I don't care what they need -- seven, six or eight [innings] -- whatever."
The big question facing the Rockies, who begin the second half two games behind the Giants in the National League Wild Card race and nine games behind the Dodgers in the NL West, is whether the bullpen needs reinforcements.
One school of thought is that Colorado could use one more experienced reliever. That was underscored when left-hander Alan Embree suffered a broken right tibia when he was hit with a line drive Friday night.
But with Corpas back and talented lefty Franklin Morales having adjusted to being in the bullpen since his recent callup, the Rockies are evaluating whether their talent level has increased without making a trade.
Corpas, the closer during the magical 2007 run to the NL pennant, believes the Rockies have most of what they need.
"The only problem right now is Embree isn't here -- he has a lot of years in the big leagues," Corpas said. "But I think I'm ready. Everybody is throwing well."
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.