James White future with Spurs is as defender.
Spurs will need to find a successor for Bruce and one player won't be enough : Bruce is able to defend Iverson one day and Zach Randolph the next one. Spurs likely won't find a player as awesome as Bruce with that kind of versatility.
White is quite long and very quick : he can be a great defender against SGs. Spurs need another player to defend against strong SF.
If Spurs sign a strong/big defensive SF or if they draft one (a player like Dominic McGuire), they will have the start of a solution for Bowen's successor.