Johnson (infection) is building up arm strength, and manager Alex Cora said the left-hander could throw a session Sunday or Monday, Zachary Silver of MLB.com reports.
Johnson has been on the shelf since June 29 with an intestinal issue and needs to add stamina to his arm. "He's good arm-wise," Cora said. "He just needs the repetitions. We're not very worried about building him up, it's just a matter of building him up, that's about it. He should be with us as soon as we feel he's comfortable as far as the innings and we're extending him long enough that he should help us." Johnson is without a firm timetable, but he could face a shorter rehab assignment if the Red Sox transition him to the bullpen. Since he landed on the injured list, Boston added starter Andrew Cashner, so Johnson is no longer needed for multiple innings every fifth day.