Peavy (back) threw off a mound Saturday for the first time since landing on the DL, John Shea of the San Francisco Chronicle reports. The session consisted of 20-25 fastballs at about 70-80 percent, and Peavy reported improvement with his condition afterward. Peavy had been limited to long toss after an MRI revealed a muscle strain and continued issues with the SI joint in his lower back in mid-April. It will be hard to know exactly where Peavy stands until he's throwing at maximum effort.