From ESPN Rumor page (no link due to needing to be an "insider")
Where Thomas will play this season
August, 15, 2013
By Nick Borges | ESPN.com
Forward DeShaun Thomas was selected by the San Antonio Spurs with the No. 58 pick in the 2013 NBA draft, however he won't play for the team this upcoming season.
According to Gigantes with translation from Sportando.net, the forward is close to finalizing a contract with Spanish side Estudiantes. The deal will likely include an NBA-out clause which will allow Thomas to get out of the contract after the 2013-14 season.
Thomas played well for San Antonio during the Las Vegas Summer League as he averaged 12.4 points, 5 rebounds and 1.2 assists, but his effort was not good enough for the Spurs to offer him a contract.
The Spurs have 14 players under contract and they may keep that spot open heading into the season. They will likely focus on the small forward position should they decide to fill the 15th spot.
Dejuan Blair is worse than Matt Bonner!