Beal suffered the injury in the first quarter of the loss Sunday to the Los Angeles Lakers. He sat on the bench after an early substitution, talked with a trainer, then went to the locker room and did not return to the court.
An MRI on Monday revealed the strain. He will be reevaluated in one week.
The Wizards travel to Chicago on Wednesday and Indiana on Friday before returning home to host the LA Clippers on Saturday.
Beal, 29, is averaging 22.9 points and 5.4 assists while shooting a career-high 52% from the field this season.
The Associated Press contributed to this story.