Dooling, and for that matter Daniels too. Both know the system, know their roles, and are able to step in at a moment's notice when injuries or foul trouble pop up.
That is exactly what you want from a 3rd string player.
Now if Doc or Danny really feels that someone like Christmas has rotation potential, so be it. However, I only keep Chrismas if they feel that way. Otherwise I keep the vets. There is no point in developing a player whose upside is the 3rd string of his position.