1. WR Buster Davis -- The former first-round pick has yet to play up to his draft status. He's been unable to shake the injury bug, a rep he carried with him out of LSU, and has failed to reach even 200 receiving yards in either of his first two seasons. However, he'll get another chance this year to nail down the slot-receiver position.
Davis has flashed some special skills during his time with the Chargers, including strong hands and the ability to run after the catch. He'll have to put it all together this season if he wants to be considered the future of the position, which is coming quickly as Vincent Jackson, Chris Chambers, Malcom Floyd and Kassim Osgood are all entering contract years.
2. FS Eric Weddle -- Weddle had an up-and-down performance last season, but he played much better after Ron Rivera took over as defensive coordinator midway through the season. He will look to carry that momentum into '09. Weddle was a tackling machine last year, pacing the team with 127 total tackles, but he'll need to do better than one interception.
Weddle should benefit as much as anyone from Rivera having all offseason to implement his attacking defense. Not only will Weddle be used as a blitzer more often, but a revamped pass rush should help him become the takeaway machine he was at Utah.
3. FS Paul Oliver -- After spending his rookie season glued to the inactive list, the 2007 supplemental pick worked his way into the rotation last season and earned extended playing time in the dime defense. All his hard work paid off in the season finale against the Denver Broncos, when his end zone interception late in the first half helped clinch the division title for the Chargers.
The competition amongst San Diego's safeties will be even stiffer this season, given the return to health of Clinton Hart and the addition of sixth-round pick Kevin Ellison. Oliver must continue to improve, as he'll jockey with Ellison and Steve Gregory for playing time throughout the season.
4. WR Legedu Naanee -- As any fantasy football player can attest, receivers often break out in their third year. The Chargers hope that's the case for Naanee, who's been one of the stars of the offseason program. Naanee has a terrific combination of size (6-foot-2, 226 pounds) and body control, as well as a knack for making big plays in big situations.
Norv Turner will move Naanee all over the field to create mismatches in his favor. However, if Naanee hopes to become more than a gadget player, he'll have to leapfrog Floyd and challenge Chambers for playing time outside the hashes.
5. ILB Brandon Siler -- Siler excels in two areas, kick coverage and goal line defense. He is one of the best in the league at chasing down kick returners, bagging 36 tackles on special teams over the last two seasons. He's equally effective playing in short-yardage situations, as he boasts the strength and downhill-instincts to attack the line of scrimmage and make plays in the backfield.
Siler has a shot to earn more playing time this season, as the team will hold an open competition at inside linebacker. Siler will challenge holdovers Tim Dobbins and Matt Wilhelm, as well as newcomer Kevin Burnett, for the right to play alongside every-down linebacker Stephen Cooper.
6. OLB Jyles Tucker – Tucker was given a golden opportunity last season, signing a new five-year, $14 million deal in the offseason before being handed a starting job in the wake of Shawne Merriman's season-ending knee injury. The results weren't what Tucker or the team hoped for, as he posted 2.5 sacks in his final nine games.
Tucker will have a hard time building on last season's progress. Not only will he have to contend with a healthy Merriman in 2009, but he'll also compete with first-round pick Larry English. The improved depth is good news for the Chargers, who had only one player finish with six or more sacks last season (Shaun Phillips with 7.5), but it also means Tucker must advance his game in a hurry if he hopes to avoid falling completely out of the rotation.
Which third-year player will shine the brightest? Talk about it in the message boards.
Michael Lombardo is a member of the Pro Football Writers of America and a long-time contributor to the Scout.com network. His analysis has been published by the NFL Network, Fox Sports and MySpace Sports. He has followed the Chargers for more than 15 years and covered the team since 2003.