He should fight Berto, Granados or Lipinets as a come back fight after losing two of his last three bouts he needs another fight like Rios.
I wouldn't mind seeing him Danny Garcia fighting a solid top 10 welterweight for his next fight but I suspect Garcia will need a bounceback win. So guys like Andre Berto, or the loser of Victor Ortiz/John Molina
Put him in with Spence, personally I think he's all wrong for The Truth, and at the very least, even if he takes another L, he'll probably acquit himself honorably, and it'll be a good barometer to tell what level Spence is truly operating on. Since the Brook match is somewhat hampered by the injury, which completely changed the complexion of the match.
Don't know what Garcia will do next but Thurman will clean out the welterweight division when he comes back.
A fight with Berto makes the most sense, then get back into position to get a title shot which wont be hard at all given his great name value in the division.
Move up to 154 and take on Hurd or Charlo. I'm sure his pop's knows he can win both those fights on the same night.