The Colorado Rapids duo claimed the top two spots in the balloting while Seattle's DeAndre Yedlin finished a distant third.
Powers finished atop the voting in all three factions — clubs, media and players — while Brown finished second in each group. Seattle Sounders right back DeAndre Yedlin was a distant third, while LA Galaxy midfielder-forward Gyasi Zardes came in fourth.
The 11th pick in the SuperDraft out of Notre Dame, Powers started 29 matches as a central midfielder for the Rapids, notching five goals and six assists. Brown, a forward, started 24 of the 31 games in which he appeared, bagging 10 goals and four assists.
The league on Monday also announced Darlington Nagbe as the winner of the Individual Fair Play award and the Galaxy as the Team Fair Play award recipient.