The teams are coming off a 1-1 game Saturday at RFK Stadium in the first leg of the round. The game, which was moved to Washington because of Hurricane Sandy, was decided by a pair of own goals in the second half.
In the 61st minute, United took the lead when sub Roy Miller scored an own goal. Just four minutes later, the Red Bulls tied it when United goalie Bill Hamid knocked the ball into the net while trying to save a deflection.
Despite the top seed, Kansas City fell in the first leg, 2-0. It'll have to rebound to try to advance to the Eastern Conference Championship.
United and Red Bulls are set to get started at 8 p.m. ET on Wednesday. The game will be shown on the NBC Sports Network.