Doolittle (shoulder) is scheduled for his first flat-ground throwing session Friday, John Hickey of the Bay Area News Group reports. Doolittle has been playing catch on flat ground, recently extending out to 120 feet without issue, but he will move it in and throw his fastball to a catcher next week. It's an important step for the left-hander, but manager Bob Melvin indicated last week that Doolittle may not make it back until late May.