I am not sure if this is based on inside knowledge by Rosen, or simply his own speculation, but he has repeatedly said in the offseason that, although Gravel can be sent down without going through waivers, he is a lock for the roster. If true, it appears that Gilbert, Troutman, Green, Fobert, and Scuderi will be competing for one roster spot and one spot as the 7th defenseman.
I think Scuderi will be sent down to save cap space and because he is not as good as the players listed. Fobert may be given another look in training camp and if Sutter has issues with him, the Kings can get a pick for him. Gilbert, Greene and Troutman can be waived without another team picking them up, so no concern there.
Injuries will obviously play a role in the defensive roster. Its good that we have options this year if someone goes down.