After undergoing running drills without experiencing any discomfort on Saturday, Doolittle took it easy Sunday with a round of long toss. Monday will be the big test.
Despite the mild setback, the A's reliever remains very much on schedule this spring, having already thrown half a dozen bullpens before camp even began.
Oakland will take it slow with another lefty, though. Newbie Drew Pomeranz was scratched from his scheduled bullpen session Saturday after experiencing an ingrown hair in his leg that had to be lanced. He played catch on Sunday, but it was unknown when he'd next get on a mound.
"Once he's comfortable moving around again," said manager Bob Melvin, "we'll get him on the field."
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.