Why would you think that Massenburg would make the active roster over Marks? Especially after Pop has said that Marks will get some minutes. And why would you want Massenburg to make it over Marks? What do you like better about Massenburg? His reputation of being a locker room problem? His inability to get do anything of significance over the course of many NBA seasons?
At least Marks is younger, more athletic, knows the system, and isn't a locker room problem.
Remember what happened last season when Adelman decided to sit Massenburg on the bench.