If I recall correctly, Wilfork had not been worked out when BB stopped his free fall. Otherwise, whomever NE drafted, they almost always worked them out and about 3/4 of them visited Gillette too. Workouts are a way for the team to answer questions, sometimes that leads to more questions, but NE wants to know what you CAN do more than what you can't, once they have that knowledge, they fit you into the picture of the team they'd like to build and assign you a draft grade.
McCourty surprised a number of people because his playing days in college did not show we fans all that he could do once he was in the NE system. Caserio and Scarnecchia at his Pro-Day, all the people looking at him over the years and at the Senior Bowl, the Combine, and BB visiting him on campus, and finally a skull session of scouts, personnel gurus, and coaches watching his film seperately and together sit down and say this kid can hold down one side of the field in press, off man, and zone with heady physicality, and make big plays if he works at finding the ball. Will he work? Yes. He's our man.