Hairston was 1-for-2 before being placed on the DL. He hurt the oblique while taking a swing during batting practice in New York. Hairston told the training staff and he has been treating the injury ever since. Hairston was able to get an at-bat against the Braves on Saturday.
But the more he swung the bat, the more pain Hairston felt. Hairston doesn't expect to be out for longer than 15 days.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.