The Phillies placed Kerkering (hamstring) on the 15-day injured list Wednesday.
Kerkering's move to the IL was a foregone conclusion after the righty reliever didn't make his Grapefruit League debut until last Friday while he recovered from a Grade 1 right hamstring strain. He was able to make another appearance Monday on the back fields of camp, but the Phillies presumably want to see the 24-year-old stack up a few more innings before clearing him to join the big-league bullpen. He'll likely be ready to start a rehab assignment when the minor-league season gets underway Friday, and he could be ready to return from the IL when first eligible April 7.