During the NBA TV broadcast of the United States' exhibition game against Spain, Smart said he's "100 percent confident" he will play in the World Cup.
Marc Stein of the New York Times reported Aug. 7 that Smart was out indefinitely due to calf tightness.
Following Team USA's practice Wednesday, head coach Gregg Popovich told reporters the Boston Celtics guard was day-to-day.
“He’s going to be a day-to-day type of thing,” Popovich said. “Probably won’t practice the next couple of days I wouldn’t think.”
The United States' roster for the World Cup has completely changed as players have withdrawn for a variety of reasons. Anthony Davis, James Harden, Damian Lillard, CJ McCollum and Bradley Beal are among the players who opted not to take part in this year's event.
Smart was named one of 17 finalists for the American squad by national team managing director Jerry Colangelo. He previously won gold medals on the Under-18 team at the Americas Championship in 2012 and with the Under-19 team at the 2013 World Championships.
Team USA will open the 2019 FIBA World Cup on Sept. 1 against the Czech Republic.