1. Wide receiver -- The perimeter passing weapons in this offense may be the worst in the NFL, which certainly handicaps Tannehill. The Dolphins' wide receivers accounted for only three touchdowns in 2012, and they had nobody to threaten a defense with the deep pass. They have two complementary receivers in Brian Hartline, who is a free agent, and Davone Bess, but neither is a difference-maker -- and the Dolphins may let Hartline hit the free-agent market. What they need is a true No. 1 WR with vertical skills to open up this offense, and this is an excellent free-agent wide receiver class. Miami has money to spend, so there are no excuses to not upgrade this position.
2. Cornerback -- This was not a great perimeter cover group in 2012, partly because of injuries and partly because of inconsistent play. Its best corner, Sean Smith, is an unrestricted free agent in a market in which there are not enough corners to fill the demand, and he might get better offers from other teams, even though the Dolphins have money to keep him. Even with a good pass rush, this secondary only produced 10 interceptions last season. By nature, the Dolphins prefer to play a lot of aggressive man schemes, but they don't have the players to get it done. They need a starting "turn-and-run corner," and, at the very least, they could use a nickel guy to cover the slot receiver if they re-sign Smith.
3. Offensive line -- The two areas of concentration here are at left tackle and right guard. Jake Long is a UFA who will demand a huge payday to re-sign, and the more film you watch on him, the less impressed you are with the level and consistency of his play. That may encourage the Dolphins to let him walk and would probably mean that right tackle Jonathan Martin would slide to the left side, where he played some last year when Long was out with an injury. That would also mean a need at right tackle, as the biggest weakness of this unit is right guard John Jerry.
4. Tight end -- Anthony Fasano is an adequate No. 2 veteran, but this passing game needs an elite pass-catching TE who can stretch defenses.
5. Safety -- While strong safety Rashad Jones is a good rising player, free safety Chris Clemons is a UFA, and he may walk. The Dolphins need more impact plays from this interior back end of the defense.
6. Linebacker -- This unit held up well in 2012, but age (middle linebacker Karlos Dansby is 31) and depth are concerns. Can they find a better middle linebacker and/or outside linebacker who could eventually start?