I’ll start this piece by saying the following up front:
Pete Carroll is good at coaching and recruiting defensive backs. The list of players who have gone on to be perennial All-Pros or starters in the league despite draft position is long. Richard Sherman, Byron Maxwell, Kam Chancellor, Brandon Browner, DeShawn Shead, Shaquill Griffin and Walter Thurmond all succeeded with the Seattle Seahawks, and (some) were coveted elsewhere despite being drafted in the 3rd round or below.
Carroll has, in the past, fostered an environment where players were rewarded for their hard work in practice.