The Wizards announced the injury Saturday, one day after Beal was a late scratch from Friday's loss to the New Orleans Pelicans.
Beal, 22, underwent an MRI on Friday and further testing Saturday. The team said he will be evaluated again in two weeks.
"It's part of the game,'' Wizards coach Randy Wittman said. "He's been through it. We know the protocol, what needs to take place. We've got to sustain without him.''
Beal is averaging a career-high 19.8 points in 17 games this season.
He has previously dealt with stress reactions in his lower right leg, missing games four separate times due to the ailment since October 2013.