15 MLS teams will play third round match winners, while the final two will play each other
U.S. Soccer released the full schedule for the 2016 Lamar Hunt U.S. Open Cup today, including the date that MLS clubs will enter the competition. After the third round of the competition on June 1, the winners of those 15 matches will be joined by the 17 MLS clubs in the fourth round on June 15.
MLS clubs will at least have an idea of their fourth round opponents whenever the third round matches are announced, as 15 of the clubs will be paired with a specific third round matchup.