USA Basketball managing director Jerry Colangelo received a call Thursday night, shortly after Kevin Durant pulled out, and was told that Gay was available if he and coach Mike Krzyzewski were interested.
"We both felt he would be a valuable addition because of his outstanding skills and the fact that he is so familiar with USA Basketball and our national team program," Colangelo said Friday in a statement. "Rudy has been an integral member of USA Basketball since 2005 and was a tremendous contributor to our 2010 world championship team. He has a lot of equity in the USA Basketball national team."
Gay, the Sacramento Kings forward, appeared in all nine games for the Americans in the 2010 world championship, averaging 7.0 points off the bench. He also was one of the last cuts made by the 2012 Olympic team.
The U.S. roster is back at 16 players. The Americans resume practice Thursday in Chicago, with the World Cup of Basketball set to begin on Aug. 30 in Spain. They will have to cut to 12 before then.
"I am extremely excited to once again be part of Team USA and its rich tradition," Gay said. "I can't wait to join my teammates in Chicago and work hard to make certain the USA takes home the gold in Spain."
The 6-foot-8 Gay averaged 20 points last season for Toronto and Sacramento. He is a good fit for the Americans because he can swing between both forward spots, which would have been filled by Durant and Paul George, who broke his right leg last week.