An early MVP candidate, Antetokounmpo had missed just two other games this season. He is averaging 26.6 points, 12.8 rebounds and 6.0 assists per game.
Bucks coach Mike Budenholzer said Friday that Antetokounmpo was injured a couple of games ago.
In Milwaukee's previous game, a 116-109 win over the Rockets on Wednesday, Antetokounmpo tallied 27 points and 21 rebounds.
In Antetokounmpo's absence against Washington, Khris Middleton led the Bucks with 25 points and eight rebounds in a losing effort.