Johnson was not in the lineup against the New York Mets and was expected to miss Thursday's series finale, as well. He strained a tendon in his wrist on a swing late in Tuesday night's game and had an MRI exam afterward.
The oft-injured Johnson missed last season while recovering from a broken leg. He is batting .220 with five homers and 20 RBIs this year. He has walked 33 times, however, giving him an excellent .415 on-base percentage.
Aaron Boone started at first base Wednesday night for the Nationals and batted in Johnson's cleanup spot.