Green, the No. 2 overall pick in the draft, exited Wednesday’s win over the Chicago Bulls in the second quarter due to the injury.
Silas said Green would be re-evaluated in a week, but there isn’t a firm timetable for his return.
The 2-16 Rockets, who are attempting to rebuild with Green as a centerpiece, snapped a 15-game losing streak with the upset of the Bulls.
Green, 19, has started every game this season. He is averaging 14.0 points, 2.3 assists and 2.7 turnovers per game while shooting 38.2% from the floor and 27.8% from 3-point range.