Thats a good question, and it's something I've been banging on about on other thread's when people put together fantasy lists of players. Ambitious players may not want to come if it's obvious they're not going to be first choice, especially if they're offered first team status elsewhere.
I'm assuming that our midfield buys will be for flexible 8s that can also do a good job at 6 (or even 10). So the question is, can Neves play competently as an 8? Answer - I don't know, but he's played most of his career at 6.