While much of the considerable attention paid to the NFL draft focuses on the first round and the top prospects, there is plenty of talent available in the later rounds. It's just a matter of finding it.
A team's draft class can be made by landing a diamond in the rough, a player who, for one reason or another, slips through the cracks for the first few rounds but ends up being a major contributor in the NFL. Sometimes it's the result of shrewd scouting, sometimes it's taking a chance on a player coming off an injury, sometimes it's dumb luck.