if the spurs are going to be serious about trying to make a playoff run, you absolutely bring him back as a reserve. if they are going to continue to take incremental steps, then theres less need for him back. we already have Fox as the full time point guard with Castle who can handle some of those duties.
but if they make a big swing for a big-name starter (whether it be durant or somebody like naz reid), then i think at that point you want to have paul back. if they just draft a couple of guys, make a mid-tier signing, and otherwise run it back, then those minutes are better off with wesley