Nationals general manager Mike Rizzo said Harper should be cleared to hit, field and run the bases "in a couple of days," having already proven his knee can handle walking, jogging and running tests. The swelling that was treated nine days ago by a cortisone shot and platelet-rich plasma injection has gone down and has not returning despite the increased activity.
"It's been good progress," Rizzo said. "That allows us to ramp it up. Now he'll go from activities to baseball activities, and we'll build from that."
Rizzo won't put a firm timetable on Harper's ultimate return to the lineup, though club officials have believed all along it could happen quickly once the 20-year-old outfielder was able to resume baseball activities. He is expected to go on a brief minor-league rehab assignment, perhaps a couple of days, before coming off the DL.
"We're just going to take it day-by-day," Rizzo said, "and see where he is the next day and see how the knee responds to that activity that day."
Once he returns, the Nationals do believe Harper will have to continue monitoring the injury, which was diagnosed as bursitis and could act up again over the course of the season.
"When it gets stressed and hit again, there's a possibility it could swell up again," Rizzo said. "It's something he's certainly going to have to monitor, and we'll see if it happens again and if we have to treat it again."