It's not that bad. For starters, he can't be traded until the offseason. Then it's 2 more years, the first one we'll have to swallow, but then he becomes expiring and for sure the Spurs will have to do some consolidation trade of sorts by then, if he rehabilitates his value it won't be hard to trade, and even if he doesn't he'll be salary ballast. 3+ years it would have been much, much worse.
As for Barlow, my guess is there will be trades coming (McDermott, Osman, Graham) and if we get back one expiring vet who can be useful to some other team, he'll be bought out (like Bullock and Payne) and that roster spot will be used to give Barlow a Champagnie style contract, probably slightly more guaranteed.