First things first, read this really good article about Marcus' struggle to make the final roster spot on the Knicks and how he was so intent on making it into the NBA he paid his own way to New York just to take part in practices.
That article also includes this really telling quote, "On a team that desperately needed to upgrade its defense, Landry can defend almost anywhere on the floor."
You'll also notice that the first paragraph of that article mentions Joe Crawford and Chris Hunter having partially guaranteed deals and goes on to assume that means their spots on the also guaranteed.
But that was two days ago.
Today, Joe Crawford and Chris Hunter were waived, the Knicks are carrying a 13-man active roster and Marcus Landry made the team.