An uncertain future in San Diego looms for the Chargers as they began their quest for just a second playoff berth in six seasons.

Their opponent Sunday in potentially their final opener in San Diego is a Detroit Lions team that's trying to prove it can return to the postseason without one of the league's top defensive forces.

With negotiations in San Diego seemingly at an impasse, the Chargers might have their eyes on heading to either one of two new stadiums planned for Los Angeles. That includes a $1.7 billion facility in suburban Carson that they could share with Oakland.

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Longtime quarterback Philip Rivers expressed hesitancy about the relocation because of concerns for his family, which will include an eighth child soon, but likely won't walk away from his lucrative contract that runs through 2019.

"My lack of excitement for a potential move was more about the thought of leaving this community than it was about a disdain for L.A.," said Rivers, who is two touchdowns shy of matching Dan Fouts' franchise mark of 254. "Again, those are still out of our control. Nobody still knows. ... This is where all but one of my children have been born and where our family has grown over a decade."

The Chargers locked up Rivers with a four-year, $84 million extension in August, but he won't have star tight end Antonio Gates for the first four games because of his performance-enhancing drug suspension.

San Diego is hoping to have built an improved offensive line in front of Rivers. He was sacked seven times in a 19-7 loss in Kansas City on Dec. 28 that cost San Diego a playoff spot with a 9-7 finish. He has been taken down at least 30 times in each of the last five seasons.

The Chargers brought in tackle Joe Barksdale from St. Louis and guard Orlando Franklin from Denver. They also signed left tackle King Dunlap to a four-year extension and moved former first-round pick D.J. Fluker from right tackle to right guard.

The line appears to have a stern test in a Detroit defense that ranked in the league's top three with 17.6 points, 300.9 yards and 69.3 rushing yards allowed per game in 2014. The Lions, though, allowed Ndamukong Suh to leave for Miami and fellow defensive tackle Nick Fairley to head to St. Louis.

They did acquire five-time Pro Bowl lineman Haloti Ngata from Baltimore but he has dealt with hamstring issues during the preseason. The Lions still have a disruptive player on the edge in Ziggy Ansah, who has 15 1/2 sacks in his first two seasons.

"Whenever our defense steps on the field, we anticipate that we should play well," defensive coordinator Teryl Austin said.

Veteran linebacker Stephen Tulloch is back after a knee injury that cost him most of 2014, but DeAndre Levy's status is unclear because of an undisclosed ailment.

Offensively, Detroit has one of the league's best receiving tandems in Calvin Johnson and Golden Tate, who is coming off a career year, and Johnson has tried to keep healthy by sitting out all four preseason games.

Johnson hasn't played in all 16 games since his record-breaking 1,964-yard, 122-catch campaign in 2012 and dealt with a high ankle sprain in 2014. He finished with 71 catches for 1,077 yards, his fewest in both categories since 2009.

Tate had a team highs of 99 receptions for 1,331 yards as the Lions finished with 11 wins for the first time since going 12-4 in 1991.

Detroit, though, once again fell short in the postseason and extended its playoff win drought to 23 seasons. That 2014 performance was still another stride away from the dark days of their 0-16 campaign that led to the Lions drafting Matthew Stafford.

The perennial 4,000-yard passer is hoping to stay a little more upright this season after taking a career-worst 45 sacks. Detroit selected guard Laken Tomlinson with its first-round pick and got another guard Manny Ramirez back into the fold after his four seasons in Denver.

Ramirez played three seasons in Detroit after being taken in the fourth round in 2007.

The Lions also drafted running back Ameer Abdullah to help a potentially ailing Joique Bell, who had a career-high 860 yards in 2014. Bell underwent surgeries to clean up knee and Achilles issues this offseason.

The Chargers will have a rookie running back on display in first-round pick Melvin Gordon, and they're hoping he can eventually prove a capable replacement for Ryan Mathews, who is now in Philadelphia.

San Diego is looking to move to 5-0 all-time at home against Detroit. The Chargers had a six-game overall win streak in the series snapped with a 38-10 defeat in the most recent meeting Dec. 24, 2011.