He's a tough guy to get. Owners won't want to dump what was probably their 1st round pick...but he's not playing like a 1st rounder at all. It is a contract year, but the O in Miami just isn't Phoenix. Try and get him yes, but it might be hard.
For the value you'll have to offer right now, its probably not worth it. If you can steal him from an owner desperate for a PG or something though, I wouldnt be surprised to see Marion get traded for someone like Kidd or Calderon, which is third or fourth round value for a first round pick. Awful risky though at this point.