The Suns also sold us Rondo for cash on draft night not too long ago, so it's not impossible that they give away another good young point guard.
... why would you think the Suns would've needed Rondo? You realize they had an effective Steve Nash, right? Besides, they didn't sell Rondo for cash; they made that pick for the Celtics since the trade was agreed to before the draft.
Marshall played last year and he was bad. Like, really bad. Check out Bright Side of the Sun to see how many Suns fans wanted to see him go. The only thing going in his favor is potential, which has yet to be realized after a year in the league.
they sold Rondo for cash, no matter how you spin it. Sure they had Nash, but that's why you keep assets for future use. They didn't even get a future pick in return, how well did that work out for them?
I'm not saying Marshall will be the next Rondo, or even a starter, but the Suns have a history of throwing away good young players. We are in rebuilding mode, and we need to collect and develop assets. Jordan Crawford, Bass, Lee, Babb, these guys are not viewed as assets by any GM, so roster space should not be an issue.