Marcel Jones??

Late round draft picks being put on the IR their rookie year is Loomis' method of keeping them from being grabbed from the practice squad.

Toon, Tiller, Jones and White were all IR this year, none were placed on PS. So they're not so much being injury prone as much as being protected for the future.

De la Puenta went straight from the PS and became the starting center. That didn't turn out so badly. The Saints grabbed him from another teams PS and only prepped him for half a season. So putting potential starters on PS you will lose some players.