Adding Nolan Carroll was a must for Cowboys' secondary

A breakdown of the first week of free agency for the Dallas Cowboys:

Most significant signing: The return of wide receiver Terrance Williams was surprising and it keeps all of Dak Prescott’s weapons intact for a second season, but Williams is the fourth target in the passing game behind Dez Bryant, Cole Beasley and Jason Witten. He is a good piece to have, but the Cowboys had to have a cornerback, so that makes Nolan Carroll the most important signing so far. Brandon Carr and Morris Claiborne are free agents and might not be back. Carroll had a solid season for the Philadelphia Eagles in 2016 and he knows the division well. He might take some chances but he had 10 pass deflections last year,…