The key departures will be losing Mason, KB and Bonner.
We have to presume that no one will take Jefferson so we are looking at Duncan, TP, Manu, Jefferson, Hill, Blair, Dice if we get Splitter and Ian, we have taken care of our bigs. Harriston could take KB's spot. Hopefully they find a place for Temple and we have 11 players who I think could all contribute to the team. That leaves two spots, one will be a draft pick (I am presuming that the Spurs will be looking for a SF because that is what we need) and then an extra defender.
If the Spurs decide to make moves, they need to focus on shooters. This was probably the worst three point shooting team Duncan has had since Avery ran the PG.