Per the official Spurs press release:
The San Antonio Spurs today announced their 2016-17 training camp roster.
The Spurs current roster stands at 20 players, and includes the additions of center Joel Anthony, guard Nicolás Laprovíttola and forward-center Ryan Richards.
Anthony (6-9, 245), a nine-year NBA veteran, spent the last two seasons with the Detroit Pistons. The UNLV product has also played for the Boston Celtics and the Miami Heat, where he spent his first six-plus seasons and won back-to-back NBA championships in 2012 and 2013. Anthony has appeared in 471 career games, averaging 2.