1. She is not needed that often:

Before I expand on this some basics about actor contracts and the difference between regular and guest characters: An actor playing a regular has certain rights, including getting credited as such and turning up in a certain number of episodes. As far as I know, a regular at White Collar gets a scene in at least ten episodes. The downside is that the actor is bond to the show and can’t take on other projects that easily. Rumor has it that this is the reason Sharif Atkins is still officially listed as a guest star. Even though Clinton Jones turns up in nearly...