Quarterback (Philip Rivers): Rivers was effective using the play-action pass in 2014, completing a league-high 82 percent of his passes for 495 yards, four touchdowns and no interceptions.
Running back (Melvin Gordon): He has a chance to break LaDainian Tomlinson’s franchise rookie rushing record of 1,236 yards.
Wide receiver (Malcom Floyd): He turns 34 on Sept. 8 and is expected to retire after the 2015 season.
Tight end (Antonio Gates): He will miss the first four games for violating the league’s policy on performance-enhancing drugs.
Left tackle (King Dunlap): He played a full season for the first time in his eight-year NFL career last season.
Left guard (Orlando Franklin): A free-agent addition this offseason, Franklin plays with a mean streak and brings toughness to the offensive line.
Center (Chris Watt): He replaces longtime starter Nick Hardwick and is expected to bring stability to the position.
Right tackle (D.J. Fluker): A 2013 first-round draft choice, Fluker lost weight this offseason to better deal with speed rushers in 2015.
Wide receiver (Keenan Allen): He focused on losing weight in order to play faster against the top cornerbacks in the NFL. Allen could see more time at slot receiver with Eddie Royal no longer on the roster.
Left defensive end (Corey Liuget): He led the Chargers in sacks the past two seasons but needs to raise his level of play another notch after receiving a lucrative contract extension.
Nose tackle (Sean Lissemore): He played a career-high 321 snaps in 2014.
Right defensive end (Kendall Reyes): The Chargers are looking for more from this Connecticut product after he totaled one sack in 2014.
Outside linebacker (Melvin Ingram): Explosive playmaker has just six career sacks in 29 career games over three seasons.
Outside linebacker (Jeremiah Attaochu): He has to stay healthy after missing five games because of a lingering hamstring injury in his rookie season last year.
Inside linebacker (Manti Te'o): The Notre Dame product is finally playing up to his potential and will serve as the defensive play-caller.
Inside linebacker (Donald Butler): He admitted to taking a step back last season, but according to defensive coordinator John Pagano, he had a strong offseason.
Cornerback (Brandon Flowers): A crafty veteran who usually is in the right place at the right time, Flowers led the Chargers last season in interceptions with three.
Cornerback (Jason Verrett): He has the potential to be a lockdown cornerback but must stay healthy.
Free safety (Eric Weddle): He is the only safety in the NFL named first- or second-team All-Pro for five straight seasons.
Place-kicker (Nick Novak): He holds the franchise record with 32 straight made field goals.
Punter (Mike Scifres): He missed the last three games of the 2014 season with a broken clavicle; he is the franchise’s all-time leader for career punting average (45.2).
Long-snapper (Mike Windt): He has been the Chargers' starting long-snapper since 2010.
Returner (Jacoby Jones): The Chargers added Jones in free agency to improve their return game. San Diego has not returned a kick or punt for a touchdown since Micheal Spurlock's 99-yard kick return against Oakland on Dec. 30, 2012.