During the summer of 2010, he played for the New Jersey Nets in the Orlando portion of the NBA Summer League and for the Miami Heat in the Las Vegas portion. For Miami, he averaged 6.6 points, 3.8 rebounds, and 0.6 blocks while playing for 14 minutes per game for five games and shooting 75 percent from the field. On September 20, Siler was invited to practice for the Phoenix Suns. One day later, the Suns decided to give him a two-year contract for the NBA's minimum salary. On January 2, 2011, the Phoenix Suns assigned Garret to the Iowa Energy for 10 games. He was later called back up to Phoenix. The Suns implemented a weight clause for Siler.[1] On January 2, 2012, after a win against the Golden State Warriors, the Suns announced that they waived Garret Siler. Siler was the first player from Augusta University (Georgia) to ever play for an NBA team. He also has the distinction of being the only John S. Davidson Fine Arts Magnet School student to play for a major professional sports team.
After taking a year off, Siler would end up playing for the Pure-Youth Construction Basketball Team in Taiwan sometime in 2015. During this time, Siler would end up helping the team get their fourth straight championship, as well as earn Championship Series MVP honors during the final matches of the season.