PHOENIX -- Giants left-hander Noah Lowry postponed his expected throwing session Monday due to mild inflammation in the back of his throwing arm.

Lowry specified that the affected area is his supinator muscle, which helps the biceps bring the hand into the supine (palm facing upward) position.

Lowry had hoped to throw off a bullpen mound for the first time since undergoing forearm surgery on March 8. But he felt discomfort in his arm and asked to undergo an MRI, which confirmed the inflammation. Lowry was encouraged that the test revealed no structural damage.

Lowry explained that he recently had intensified his throwing on flat ground, which likely caused the inflammation. "But in the grand scheme of things, it's just a small bump in the road," said Lowry, who expects to rest for a couple of days before resuming his throwing program. "I'm getting that extension and 'whip' on the ball that I might not have had for about a year."

Lowry, 27, added that there was no connection between the inflammation and his surgery.

Manager Bruce Bochy endorsed Lowry's caution. "I said, 'Hey, we're in April. I don't want you to rush this thing,' " Bochy said he told Lowry.

Lowry, the Giants' leading winner in 2005 (13 victories) and 2007 (14), has been playing catch on flat ground for close to a month.