So basically Caleb Williams may have screwed Fields (and the Bears) over by rescheduling his visit to the Bears. IIRC he was supposed to come to Halas Hall last week and the Bears really wanted him to come but he insisted on visiting next week.
So now assuming the Bears continue the path of moving forward with Caleb, Fields won't have an option to be a starter anywhere and the Bears will likely get less in return for him. Possible that he wouldnt have been a starter regardless but I'm sure both Fields and the Bears would have preferred to have this resolved already.