San Antonio Spurs guard De'Aaron Fox was named by NBA commissioner Adam Silver to replace forward Antetokounmpo in Sunday's contest among elite players at Los Angeles.
The event features a World team of top global talent and two teams of Americans, USA Stars and USA Stripes, in a mini-tournament.
Fox will be added to the USA Stripes squad, which will send Miami's Norman Powell, who has ties to Jamaica, to the World lineup.
Antetokounmpo joins a list of All-Star selections who will not be competing in the contest that includes reigning NBA Most Valuable Player Shai Gilgeous-Alexander of Oklahoma City and Stephen Curry of Golden State.
Los Angeles Lakers star Luka Doncic is also in doubt after being ruled out for Thursday's NBA game against his former club, the Dallas Mavericks.
The NBA Rising Stars event also lost Dallas teen forward Cooper Flagg, last year's top pick in the NBA Draft, and French centre Alex Sarr of Washington.
Fox was given his second All-Star selection, the other coming in 2023. He is averaging 19.4 points, 3.8 rebounds, 6.3 assists and 1.27 steals for the Spurs, who are 38-16 and second in the Western Conference.