Who gets Spurs last roster spot?

The San Antonio Spurs now have 14 players signed to guaranteed contracts for the 2013-14 season after Tiago Splitter finalized his four-year, $36 million deal over the weekend. The Spurs often leave an open roster when each season begins, which means they could be done. If that's the case then Gary Neal and rookie Deshaun Thomas won't have a spot on the team.