Athletics relief pitcher Grant Balfour threw off a mound for the first time since having arthroscopic knee surgery last month and could be ready for game action within two weeks, the San Francisco Chronicle reports. Balfour mixed his entire arsenal during the 25-pitch session and said he experienced only minor stiffness in his knee. "I have to, I'm going to need it," he said about his rapid rehab schedule. "It's going to take me a full month to get ready."