The Tar Heel quartet is made up of Corey Ashe, Matt Hedges, Dax McCarty and Sheanon Williams.
Ashe, a veteran defender for Houston, has started 15 matches and ranks second on the club with three assists.
Hedges is the only player to start all 16 games for FC Dallas. The defender has two goals on only four shots and also has one assist to his credit.
Midfielder McCarty has made 13 starts and 14 appearances for the New York Red Bulls. He has one goal and one assist in his 10th season in MLS.
Williams, a defender for Philadelphia Union, has made nine starts and played in 10 matches. He has one goal in his fifth season in Philly.
MLS fans can vote for 11 players - the All-Star Fan XI - who will then be made available for head coach Caleb Porter to sue for the match in Portland's Providence Park.
The MLS squad will face Bundesliga champions Bayern Munich.
Porter, whose full-time job is head coach of the Portland Timbers, will ultimately select the gameday roster and the starting lineup from the list of players made available to him as determined by media, fans, players and two picks made by MLS commissioner Don Garber that will be announced in July.
A total of 32 All-Stars are named each year - 4 goalkeepers, 8 defenders, 13 midfielders, 7 forwards - per the MLS-MLSPU Collective Bargaining Agreement and the full list of inactive players - those not selected to the gameday roster - will be revealed on August 6 on MLSsoccer.com.