Boggs was acquired on July 9 from the Cardinals in exchange for an international signing bonus slot and appeared in just two games with the Rockies before he was sent to Triple-A Colorado Springs. He didn't allow a run in 1 2/3 innings with the Rockies but struggled mightily for the first two months of the year with the Cardinals.
This came after a 2012 season in which Boggs was a shutdown reliever for St. Louis with a 2.21 ERA in 73 1/3 innings. Rockies manager Walt Weiss said command is the key for Boggs to return to his old form.
"Just staying away from the big misses and misfiring with that power sinker he's got," said Weiss, who plans to use Boggs in some late-inning situations. "If it's around the plate, hitters are going to fire at it. It's the big misses I think that get him into bad counts and into some trouble. But the stuff for me is really interesting."
Corpas, the closer on the 2007 Rockies squad that made the franchise's only World Series appearance, was back with Colorado from early June until Aug. 11. Inconsistency plagued Corpas earlier this year, as he had a 4.50 ERA in 19 appearances.
McHugh made a spot start for the Rockies on July 27 but will move to the bullpen for his second stay in Denver. He gave up six runs over five innings in that lone start, a 7-5 loss to the Brewers, before the club shipped him back to Colorado Springs.
Wheeler returns to the big leagues only a week after the Rockies optioned him to Triple-A. He went 4-for-19 during his first stint with the Rockies this year, and has played first and third base. Wheeler excelled in Triple-A, hitting .306 with 12 homers and 89 RBIs over 116 games for the Sky Sox.
Weiss said he prefers not to view the rest of the schedule as a tryout for September callups, but he wants to make sure they get a taste of the Majors.
"I'm going to try to keep guys involved," he said. "If you watched all year, I don't like guys sitting around for too long. September's a little bit different -- we got a lot of bodies, so it's a little bit tougher. But I like getting guys involved and seeing what they bring."
Ian McCue is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.