Here is a list of 2014's Upcoming Free Agent market.
For me, the most alluring position groups on this list (other than WR, where some good talent, and every explosive white-guy receiver, is on the market) are in the defensive front 7 - there are some quality players available there. DT BJ Raji stands out, as does Brian Orakpo at OLB. Whether OLB is a position of need is debatable, with Freeney coming back and Ingram showing promise, they may be ok with the pieces in place. But I would never hesitate to add another talented pass rusher to any team.
DL was supposed to be a strongpoint this year and was not at all. It may not be possible to draft a game-changer on the line, and this is where I believe the Chargers should make a big free agent signing. A veteran like Jared Allen or Justin Tuck, though perhaps losing a step, would add a ton of experience and mentorship to rawer talents ilke Reyes and Liuget. (The price tag on former Pro-Bowl veterans, however, may be entirely too high to sign away from another team).
Here's how I see the position groups as they should be prioritized in the draft, and any other free agent signings.
POSITIONS of NO REAL NEED: QB, RB
A late pick or un-drafted QB, for practice squad depth and to be a plan-B to Sorenson, is it.
The combo of Matthew and Woodhead is potent and I think can be counted on to produce again. But RB is a position where if a player of a certain caliber is available in the draft, you take them and find room on the roster later.
POSITIONS NEEDING SOME UPGRADE OR DEPTH: TE, WR, S, LB
At each of these spots there is some solid talent in place already, but depth and competition wold be welcome. Ledarius Green is exciting, but he can't be the only good TE on the roster, with Gates in the twilight of his career. Telesco should be looking for a TE that is above-average in the run game but can also sneak downfield to make a catch (a la Brandon Malalanaeuna??). Not one that is average at blocking AND catching. Personally I don't know why more teams don't employ 2 pass-catching threats at TE like the Patriots had a few years ago - it was near unstoppable. With the WR group not so explosive all throughout the depth chart, it would make sense to seek another downfield threat at TE.
WIth Keenan Allen exploding, and Malcom Floyd coming back, it may not seem like a real need. However, the receiving corps would greatly benefit from one more dynamic playmaker. Eddie Royal is back one more year but is probably not the long-term answer in the slot. Vincent Brown had become a dud and needs a drastic turnaround or else replacement. The inability of any receiver not named Keenan to get open hurt the Chargers in the playoff loss - Denver just keyed in on Allen and Gates and so there was nowhere to throw. Adding an exciting slot receiver or viable #2/#3 would take pressure off Allen, Floyd, Gates and Green, and another downfield threat would make the passing attack a serious threat to any defense.
Safety appeared to be a real problem early in the year. With Weddle back in position and back in form, made possible by the play of Addae, there is now a solid starting tandem. Stuckey and Brandon Taylor are prospects that may yet turn into quality players, but the chance to draft a dynamic SS would be hard to overlook, even if just to be a more solid backup. We don't know whether Taylor or Stuckey will ever reach starter-level.
The LB corps is a little hard to gauge (isn't it always in SD?) On one hand, with Freeney and Melvin Ingram rotating around Jarret Johnson, the OLB spot seems pretty well covered. And though Telesco made a statement by trading up to get Te'o, showing that he's their guy, there needs to be alternatives to step up if Te'os play doesn't improve. There's also a possibility Donald Butler doesn't re-sign, in which case the ILB group is suddenly a real need.
POSITIONS OF MOST NEED: CB, OL, DL
I hear that the 2014 draft is rich in CB talent. Not being a draft guru, I won't offer analysis of top prospects. Let us hope Tom Telesco is in the position to make a "winning" pick in the early rounds, maybe even an instant-starter wuth their first pick. This is the position where one key player could make the single biggest impact. Adding that elite corner who can play on an island and shut-down an opponents #1 receiver has a tremendous effect . It shrinks the field for the rest of the defense, making teammates more aggressive and effective (eg: allowing for more blitzes, simplifying coverage for LBs and safeties in the middle of the filed and up the seam).
The OL is missing a stud at RG. I probably am not the only fan calling for Jeremy Clary to lose his job, or at least his starting role. Although the playoff loss to Denver showed Clary to be perhaps a little underrated (the right side was a disaster without him), and there have been games where he was clutch in protection, but he is undoubtedly the weak link in the running game. This OL has the pieces to become a dominant, dictating run game, and Clary does not seem to have the skill or athleticism to be an adequate zone blocker (when asked to pull left in "power" run scheme, he is likewise a turd).
The OL has shown good depth, with backups often performing above expectations at each position. There is a definite need for reinforcement at LT. If Telesco can select a promising project-pick, or even a higher-round pick that could challenge for the starting spot, then the OL would suddenly seem quite solid. The only other question mark lies with longevity of the other interior players. Hardwick can not be counted on to play at a high level past another few years, but Ohrnberger has shown promise. Also Rinehardt had only signed a one-year contract for 2013, but Troutman could conceivably be an answer.
Another difficult position group because of the lack of consistency of the players over the last two years. It remains to be seen if 2012 was an apparition for the excellent DL play, or if 2013 is a better indication. DT presence was lacking this year, and that an upgrade in the center would boost the rest of the line (this is always true, of course). I don't know how Pagano values Cam Thomas and Lissemore going forward, but personally if I were Telesco I would target a beast to take over or at least to compete at DT. It would also be a priority to find a free agent or draft pick that can step up at DE. Reyes hasn't played with starter-level talent. Not giving up on him as a future starter, but I'd look to add a playmaker that will elevate the DE play, or else at least provide competition to the other starters and more quality depth.