The main problem I see with Marquis Daniels is he's not a good outside shooter and ideally we would get somebody who could hit corner 3's if left open like Posey did. Daniels is also not known as a great defender, and good defense is another thing we need from our wing backup.
However, if we acquired Daniels but then picked up a guy who can defend well and hit open 3's like Dahntay Jones, Keith Bogans, or Ime Udoka, then I wouldn't mind having Daniels.
We'd still need to get a backup center somehow, though. I like the idea of trading for Diop, he's just the kind of guy we need. Big, long, and good on defense. He also plays for a team that seems likely to give up a decent player in return for expiring contracts.