When USA Basketball announced a 20-man roster for training camp ahead of the FIBA World Cup, it appeared coach Gregg Popovich would have to make some tough choices to cut down to a 12-man tournament roster. 

With less than two weeks to go before camp opens in Las Vegas, though, Popovich and managing director Jerry Colangelo are now trying desperately to hold on to players already committed while recruiting replacements for the ever-growing list of withdrawals. 

Damian Lillard is the latest high-profile player to pull out, The Athletic and Yahoo Sports reported Tuesday. He follows James Harden, Anthony Davis, Bradley Beal, Tobias Harris, CJ McCollum and Eric Gordon in withdrawing from the team within the past 10 days. 

USA Basketball also had indicated it might elevate No. 1 overall pick Zion Williamson from the select team set to provide training camp opposition to the senior team, but the Pelicans' new franchise player also has pulled out. 

The exodus has reached the point that a player who was not on the initial roster released last month, Spurs forward DeMar DeRozan, accepted an invitation from USA Basketball but has since bailed out, The Athletic reported Tuesday. 

On the flip side, reinforcements are starting to roll in. Celtics forward Jaylen Brown and Knicks forward Julius Randle have accepted invitations to the Aug. 5-9 camp in Las Vegas, according to The Athletic. 

More additions and subtractions to the roster seem likely before then, particularly with Kyle Lowry — who has said he still hopes to play for Team USA — coming off thumb surgery. 

The only players remaining on the U.S. camp roster with World Cup or Olympics experience are Lowry, Kevin Love, Andre Drummond and Harrison Barnes. 

Following the Vegas camp, the team will relocate to Los Angeles for more practice Aug. 13-15 before playing Spain Aug. 16, and the 12-man World Cup roster will be announced the following day. 

After a series of practices and exhibitions in Australia in late August, the U.S. will open group play in Shanghai on Sept. 1 against the Czech Republic.