SFDC Opportunity field - Primary Campaign Source: Can this field be used in MKTO?

We have several custom fields on Opportunity which we want to use for creating filter/triggers on List and Campaign in MKTO.

The Primary Campaign Source is a standard lookup Campaign field on the Opportunity object. However, under the Opportunity Info page in MKTO I do not see the Campaign field. Is there a way to utilize this Campaign field on the Opportunity? I was told that this standard field should be visible and available for use in MKTO but I cannot seem to find it anywhere.