Vizcaino, 33, hasn't pitched since April 2 and was placed on the 15-day disabled list after not being able to loosen up for a game against the Braves on April 5. He was throwing bullpen sessions and was scheduled to have a live batting practice session Saturday when soreness returned.
Rockies head athletic trainer Keith Dugger said the MRI confirmed that there wasn't a major injury. But the Rockies are going to back away from having Vizcaino on a throwing program until the inflammation calms.
Vizcaino, whom the Rockies signed to a two-year, $7.5 million contract after he made a career-high 77 appearances for the Yankees last season, made two appearances and gave up four runs in 1 2/3 innings before the injury.
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.