The move would be to clear out cap space if they decide that LMA isn't working out. Unless they can swap him for rotation players fit needs and aren't overpaid, I view this is the next best option. Spurs likely aren't getting a lottery pick for him, nor are they getting an upgrade, they probably won't even get equal value in comparison to LMA at his best. Admittedly, the trade is underwhelming from a return standpoint; cap space, a 32nd pick and another pick, that would probably be in the late teens is a low return for the second best player on a team that may make the WCF and win 63 games. I don't think it's terrible, however, for a former all star player that is entering the final year of his deal and will be 32 and coming off a season where he is averaging only 17.5 ppg. If the Spurs wanted to try for Bender or Chriss; I don't know if it would be a deal breaker for Phoenix, they haven't made the playoffs in 8 years and I would assume that they're desperate to try and get back.
I've already been down the "Spurs requiring Hill" road with TD21. I came down on the side that the Spurs would try and dump Gasol not LMA, resign Mills, add Hill, and resign Dedmon to be the starting C (Mills, Hill, Anderson, Bertans, Lee as the bench) before being convinced that while it's possible, it would effectively keep Murray from getting consistent minutes to develop.
I don't believe that playing $40 million to Parker, Mills, Murray, and Hill for one season is all that big of an issue, so long as the team doesn't go in to the luxury tax to field an imbalanced roster. I don't believe that that would be an imbalanced roster. Parker is ,probably, going to make less than $10 million after next season, and that $40 million dollar figure would drop to around $35 million for 3 rotation players and a prospect for the next two or three years.
My LMA trade was more specially in response to CDG, who mentioned restructuring Gasol and moving LMA. I don't think both would happen; and I don't know how much a Gasol restructuring would help, I can't find a scenario where the Spurs could fit both Mills and Dedmon under the cap without trading Gasol for cap space, let alone going after Hill. I'm fine with Aldridge; though he can be maddeningly inconsistent and ,to a lesser extent, Gasol, though, I'd prefer he stay coming off the bench. I would hope that the Spurs can keep Mills, Dedmon, and Lee (though I'm curious to see Bertans as a full time backup PF).