Free-agent point guard Patty Mills will have shoulder surgery for a rotator-cuff injury that bothered him during the season and will likely be out until at least January, sources told ESPN.com's Marc Stein on Tuesday night.
Mills scored 17 points in the Spurs' clinching Game 5 of the NBA Finals over the Miami Heat.
The Sydney Morning Herald of Australia earlier reported the news of Mills' surgery, which he was to undergo in coming days after scans revealed the extent of the injury.
The newspaper reported Mills has withdrawn from Australia's campaign for the Aug. 30 to Sept. 14 World Cup in Spain.
The Aussie is a free agent but sources told Stein he's expected to re-sign with the Spurs as the sides have already begun talks on a new deal.
Mills, a second-round draft pick by Portland in 2009, averaged 10.2 points in 18.9 minutes per game for the Spurs in his fourth full season, hitting a career-high 135 3-pointers.