New Orleans needs to change its roster after a bad start. Bledsoe does not fit for them, so they move off his contract and get a wing defender theh desperately need in Ariza and Moose a stretch 5 that they also need. Ariza might not play, however if he does come back it would be a boost and they don't give up much for him anyway, plus move off Bledsoes contract.
The Thunder will move off two veteran expiring contract and get more picks, even if it means taking on Bledsoes contract as they won't really sign any FAs from cap space anyway.