General manager John Mozeliak said the organization will now revise Harris' throwing program to begin the process of slowly building back his arm strength. The Cardinals expect to have a better feel for when Harris might begin a Minor League rehab assignment in about 10 days.
An MRI taken of Harris' elbow revealed no structural concerns.
Harris, a Lieutenant in the United States Navy, made his Major League debut with the Cardinals last season. He posted a 3.67 ERA over 26 appearances.
Jenifer Langosch has covered the Cardinals for MLB.com since 2012, and previously covered the Pirates from 2007-11. Read her blog, By Gosh, It's Langosch, follow her on Twitter @LangoschMLB, like her Facebook page Jenifer Langosch for Cardinals.com and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.