SAN DIEGO (AP) -- The Chargers expended a lot of effort reworking their offensive line in the offseason.

They're hoping that pays dividends during their season opener Sunday against the visiting Detroit Lions.

Left tackle King Dunlap is the lone returning starter at the same position from last year's opening day. Otherwise it's a mix-and-match of newcomers and others playing fresh positions.

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Left guard Orlando Franklin was signed away from Denver. Center Chris Watt is a converted guard, although he started five games at center last year. Right guard D.J. Fluker spent his first two Chargers seasons at right tackle. Left tackle Joe Barksdale came over from the Rams.

Add it up and it's not clear what the Chargers, who were 30th in rushing last year, have along their front line. Its play was uneven in the preseason as quarterback Philip Rivers was hit often and the running lanes, even for first-round pick Melvin Gordon, were difficult to locate.

"It's a different group but one I think has a lot of confidence together and one I have a lot of confidence in," Rivers said. "They have really come together in the last four or five months and settled into their spots and they have meshed well."

It figures to be a big challenge on Sunday. The middle of the Lions' defensive line no longer features Ndamukong Suh, but it has someone just as stout in Haloti Ngata. Detroit finished last year ranked No. 1 in stopping the run.

"I got a ton of confidence in them all," coach Mike McCoy said of his offensive linemen. "They're getting better every day. The more they play together, like any group of players, the more the 11 guys play together with each other the better they are going to be."

The Chargers will be missing Pro Bowl tight end Antonio Gates on Sunday. He is serving the first of his four-game suspension for violating the NFL's policy on performance-enhancing drugs. Gates, who led the Chargers with 12 scoring receptions last year, isn't allowed to practice.

"The thing I noticed most is not having him in the locker room," Rivers said. "It was weird. This was the first Wednesday since I've been a Charger that he hasn't been in there. The conversation, the cutting-up, the laughter in there before meetings, that was where you go, `Golly, that's crazy.' Certainly we will miss him."

Ladarius Green replaces Gates in the lineup, though Green was being examined because of concussion-like symptoms after practice. No other update was provided by the team.