In terms of pure personnel impact, the first few days of free agency are up there with draft weekend in the NFL. With the draft coming months after franchises attempt to sign players, teams first get a chance to fill spaces on their roster with veterans before trying to pigeonhole their premier picks to depth-chart weaknesses on draft day.
Team needs can drastically change over the course of just a few days. The Houston Texans no longer need a quarterback after signing Brock Osweiler. The Miami Dolphins had a need at defensive end with Olivier Vernon already one foot out of the door, but after they signed Mario Williams, they were able to quickly end the talk of drafting a pass-rusher in the first round.
"Best player available" is a term thrown around often, but at some point, you're building a football team, not just collecting talent. We'll go over every franchise's biggest need as it stands today, including explaining why positions are needs and pinpointing who the top four to five prospects are at those positions.